diff --git a/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/Part.java b/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/Part.java
index 055a0050d3beb3581f30d6d8013128ad92939d1d..82c880d5ce6978b14f1dc8220acab6cc700085cf 100644
--- a/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/Part.java
+++ b/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/Part.java
@@ -36,10 +36,6 @@ public interface Part {
 
     long getSize();
 
-
-    void write(String fileName) throws IOException;
-
-
     void delete() throws IOException;
 
     default String getHeader(HeaderName name) {
diff --git a/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/PartImpl.java b/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/PartImpl.java
index e6ffea806d97e25bfabdf55f416e7ecab0d421d3..cf3aef77800156853161d02287769171669a6895 100644
--- a/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/PartImpl.java
+++ b/feat-core/src/main/java/tech/smartboot/feat/core/common/multipart/PartImpl.java
@@ -14,14 +14,8 @@ import tech.smartboot.feat.core.common.HeaderName;
 import tech.smartboot.feat.core.common.HeaderValue;
 import tech.smartboot.feat.core.common.FeatUtils;
 
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
+import java.io.*;
 import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
@@ -47,9 +41,9 @@ public class PartImpl implements Part {
     private OutputStream diskOutputStream;
 
     /**
-     * 表单域大小
+     * 大小
      */
-    private int formSize;
+    private int partSize;
 
     /**
      * 磁盘文件
@@ -70,6 +64,9 @@ public class PartImpl implements Part {
         if (fileName == null && inputStream == null) {
             throw new IllegalStateException();
         }
+        if (inputStream == null && thresholdBuffer != null) {
+            inputStream = new ByteArrayInputStream(thresholdBuffer.toByteArray());
+        }
         if (inputStream != null) {
             return inputStream;
         }
@@ -100,25 +97,10 @@ public class PartImpl implements Part {
         if (diskFile != null) {
             return diskFile.length();
         } else {
-            return formSize;
+            return partSize;
         }
     }
 
-    @Override
-    public void write(String fileName) throws IOException {
-        if (this.diskFile == null) {
-            return;
-        }
-        Path target = Paths.get(fileName);
-        if (!target.isAbsolute()) {
-            if (FeatUtils.isNotBlank(multipartConfig.getLocation())) {
-                target = Paths.get(multipartConfig.getLocation(), fileName);
-            } else {
-                target = File.createTempFile("feat_" + this.hashCode(), fileName).toPath();
-            }
-        }
-        Files.move(diskFile.toPath(), target, StandardCopyOption.REPLACE_EXISTING);
-    }
 
     @Override
     public void delete() throws IOException {
@@ -206,10 +188,48 @@ public class PartImpl implements Part {
     }
 
     public void setFormSize(int formSize) {
-        this.formSize = formSize;
+        this.partSize = formSize;
+    }
+
+    private ByteArrayOutputStream thresholdBuffer;
+    public void write(byte[] bytes) throws IOException {
+        if (multipartConfig.getFileSizeThreshold() > 0) {
+            //如果有 FileSizeThreshold 配置？
+            if (thresholdBuffer == null) {
+                thresholdBuffer = new ByteArrayOutputStream();
+            }
+
+            if (thresholdBuffer.size() < multipartConfig.getFileSizeThreshold()) {
+                thresholdBuffer.write(bytes);
+            } else {
+                //如果超出了 FileSizeThreshold 大小？
+                getDiskOutputStream().write(thresholdBuffer.toByteArray());
+                getDiskOutputStream().write(bytes);
+            }
+        } else {
+            getDiskOutputStream().write(bytes);
+        }
+    }
+
+    public void flush() throws IOException {
+        if(diskOutputStream != null) {
+            diskOutputStream.flush();
+            thresholdBuffer = null;
+        }
+
+        if(thresholdBuffer != null){
+            partSize = thresholdBuffer.size();
+        }
+    }
+
+    public void close() throws IOException {
+        if (diskOutputStream != null) {
+            diskOutputStream.close();
+            thresholdBuffer = null;
+        }
     }
 
-    public OutputStream getDiskOutputStream() throws IOException {
+    private OutputStream getDiskOutputStream() throws IOException {
         if (fileName == null) {
             throw new IllegalStateException();
         }
diff --git a/feat-core/src/main/java/tech/smartboot/feat/core/server/impl/MultipartFormDecoder.java b/feat-core/src/main/java/tech/smartboot/feat/core/server/impl/MultipartFormDecoder.java
index ba3213fee4ef9ece9968456f586185f81d067014..99b0ba602c79cc325e7822f4056d6cb119e6e5cb 100644
--- a/feat-core/src/main/java/tech/smartboot/feat/core/server/impl/MultipartFormDecoder.java
+++ b/feat-core/src/main/java/tech/smartboot/feat/core/server/impl/MultipartFormDecoder.java
@@ -218,13 +218,13 @@ class MultipartFormDecoder {
                     }
                 }
                 try {
-                    currentPart.getDiskOutputStream().write(bytes);
+                    currentPart.write(bytes);
                     if (boundaryLimit >= 0) {
                         if (byteBuffer.get() != FeatUtils.CR || byteBuffer.get() != FeatUtils.LF) {
                             throw new HttpException(HttpStatus.BAD_REQUEST);
                         }
-                        currentPart.getDiskOutputStream().flush();
-                        currentPart.getDiskOutputStream().close();
+                        currentPart.flush();
+                        currentPart.close();
 
                         currentPart = null;
                         state = STATE_END_CHECK;