diff --git a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/io/serialization/jce/JceDecoder.kt b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/io/serialization/jce/JceDecoder.kt
index 35047be7d..b63bbaf42 100644
--- a/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/io/serialization/jce/JceDecoder.kt
+++ b/mirai-core-qqandroid/src/commonMain/kotlin/net/mamoe/mirai/qqandroid/io/serialization/jce/JceDecoder.kt
@@ -36,12 +36,14 @@ internal class JceDecoder(
         )
     }
 
-    fun SerialDescriptor.getJceTagId(index: Int): Int {
+    private fun SerialDescriptor.getJceTagId(index: Int): Int {
         return getElementAnnotations(index).filterIsInstance<JceId>().single().id
     }
 
 
-    private val ByteArraySerializer = ByteArraySerializer()
+    companion object {
+        private val ByteArraySerializer: KSerializer<ByteArray> = ByteArraySerializer()
+    }
 
     // TODO: 2020/3/6 can be object
     private inner class SimpleByteArrayReader : CompositeDecoder by this {
@@ -64,16 +66,14 @@ internal class JceDecoder(
     // TODO: 2020/3/6 can be object
     private inner class ListReader : CompositeDecoder by this {
         override fun decodeSequentially(): Boolean = true
-        override fun decodeElementIndex(descriptor: SerialDescriptor): Int {
-            error("should not be reached")
-        }
-
+        override fun decodeElementIndex(descriptor: SerialDescriptor): Int = error("should not be reached")
         override fun endStructure(descriptor: SerialDescriptor) {
             println("endStructure: ${descriptor.serialName}")
         }
 
         override fun decodeCollectionSize(descriptor: SerialDescriptor): Int {
-            return jce.useHead { jce.readJceIntValue(it) }
+            // 不读下一个 head
+            return jce.currentHead.let { jce.readJceIntValue(it) }.also { println("listSize=$it") }
         }
     }
 
@@ -86,24 +86,23 @@ internal class JceDecoder(
 
     override fun beginStructure(descriptor: SerialDescriptor, vararg typeParams: KSerializer<*>): CompositeDecoder {
         println("beginStructure: ${descriptor.serialName}")
-        if (descriptor == ByteArraySerializer.descriptor) {
-            println("!! ByteArray")
-            println("decoderTag: $currentTagOrNull")
-            println("jceHead: " + jce.currentHeadOrNull)
-            return jce.skipToHeadAndUseIfPossibleOrFail(popTag().id) {
-                println("listHead: $it")
-                when (it.type) {
-                    Jce.SIMPLE_LIST -> SimpleByteArrayReader().also { jce.prepareNextHead() } // 无用的元素类型
-                    Jce.LIST -> error(""); //ListReader()
-                    else -> error("type mismatch. Expected SIMPLE_LIST or LIST, got ${it.type} instead")
-                }
-            }
-        }
         return when (descriptor.kind) {
             StructureKind.MAP -> {
                 error("map")
             }
-            StructureKind.LIST -> ListReader()
+            StructureKind.LIST -> {
+                println("!! ByteArray")
+                println("decoderTag: $currentTagOrNull")
+                println("jceHead: " + jce.currentHeadOrNull)
+                return jce.skipToHeadAndUseIfPossibleOrFail(popTag().id) {
+                    println("listHead: $it")
+                    when (it.type) {
+                        Jce.SIMPLE_LIST -> SimpleByteArrayReader().also { jce.prepareNextHead() } // 无用的元素类型
+                        Jce.LIST -> ListReader()
+                        else -> error("type mismatch. Expected SIMPLE_LIST or LIST, got ${it.type} instead")
+                    }
+                }
+            }
 
             else -> this@JceDecoder
         }
diff --git a/mirai-core-qqandroid/src/commonTest/kotlin/net.mamoe.mirai.qqandroid.io.serialization/JceInputTest.kt b/mirai-core-qqandroid/src/commonTest/kotlin/net.mamoe.mirai.qqandroid.io.serialization/JceInputTest.kt
index 63b7d54f7..eed7b65e4 100644
--- a/mirai-core-qqandroid/src/commonTest/kotlin/net.mamoe.mirai.qqandroid.io.serialization/JceInputTest.kt
+++ b/mirai-core-qqandroid/src/commonTest/kotlin/net.mamoe.mirai.qqandroid.io.serialization/JceInputTest.kt
@@ -45,7 +45,7 @@ internal class JceInputTest {
         @Serializable
         data class TestSerializableClassA(
             @JceId(0) val byteArray: ByteArray = byteArrayOf(1, 2, 3),
-            @JceId(3) val byteArray2: ByteArray = byteArrayOf(1, 2, 3, 4)
+            @JceId(3) val byteArray2: List<Byte> = listOf(1, 2, 3, 4)
         ) {
             override fun equals(other: Any?): Boolean {
                 if (this === other) return true
@@ -54,14 +54,13 @@ internal class JceInputTest {
                 other as TestSerializableClassA
 
                 if (!byteArray.contentEquals(other.byteArray)) return false
-                if (!byteArray2.contentEquals(other.byteArray2)) return false
+                if (byteArray2 != other.byteArray2) return false
 
                 return true
             }
-
             override fun hashCode(): Int {
                 var result = byteArray.contentHashCode()
-                result = 31 * result + byteArray2.contentHashCode()
+                result = 31 * result + byteArray2.hashCode()
                 return result
             }
         }