diff --git a/MyCode/App_Auto.c b/MyCode/App_Auto.c
index 5762bf1..19b8b36 100644
--- a/MyCode/App_Auto.c
+++ b/MyCode/App_Auto.c
@@ -329,9 +329,19 @@ static int App_Auto_MapNoteOn(int channel, int key)
 static void Func_CallBack_ProgramChange(int channel, int program)
 {
     MidiFifoItem_t midimsg;
+    uint8_t ch = (uint8_t)(channel & 0x0F);
     LOG_I("REG", "pc ch%u prog=%d", (unsigned)channel, program);
-    midimsg.msg[0] = 0xc0 | (channel & 0x0F);
-    midimsg.msg[1] = program;
+    /* 双音色库：伴奏一律先切 Bank0（CC0 MSB=0, CC32 LSB=0）再 PC */
+    midimsg.msg[0] = 0xb0 | ch;
+    midimsg.msg[1] = 0x00;              /* CC0 Bank MSB */
+    midimsg.msg[2] = MIDI_BANK_ACCOMP;
+    midimsg.msglen = 3;
+    mymidififo_InQueue(&m_MidiSendFifo,&midimsg);
+    midimsg.msg[1] = 0x20;              /* CC32 Bank LSB */
+    midimsg.msg[2] = 0;
+    mymidififo_InQueue(&m_MidiSendFifo,&midimsg);
+    midimsg.msg[0] = 0xc0 | ch;
+    midimsg.msg[1] = (uint8_t)program;
     midimsg.msg[2] = 0;
     midimsg.msglen = 2;
     mymidififo_InQueue(&m_MidiSendFifo,&midimsg);
diff --git a/UI/UI_Idle.c b/UI/UI_Idle.c
index 6c55895..4045b7c 100644
--- a/UI/UI_Idle.c
+++ b/UI/UI_Idle.c
@@ -85,7 +85,14 @@ extern int8_t delta;
 extern STRING_MIDI USE_MIDI;
 void LoadConfig(void)
 {
-    SendProgramChangeMidiEvent(0,Timbre_index[mGuiData[GUI_TIMBRE_SELECT].Current]);
+    uint8_t ch;
+
+    /* 双音色库：主弦走 Bank1，先选 bank 再 PC */
+    SendProgramWithBankMidiEvent(0, MIDI_BANK_STRING, Timbre_index[mGuiData[GUI_TIMBRE_SELECT].Current]);
+
+    /* 伴奏通道预置 Bank0，避免上电后首个 PC 前误用残留 bank */
+    for (ch = 1; ch <= 15; ch++)
+        SendBankChangeMidiEvent(ch, MIDI_BANK_ACCOMP);
 
     uint8_t val_127 = (faders[0].val * 127) / 10;
     SendVolumeChangeMidiEvent(1,val_127);
diff --git a/UI/UI_global.c b/UI/UI_global.c
index 27cea57..6cb729a 100644
--- a/UI/UI_global.c
+++ b/UI/UI_global.c
@@ -942,7 +942,8 @@ void label_TimbreSelece_ui(const LEBEL_UI *UI, GUI_SWITCH * Group)
 	switch(Group->Id)
 	{
 		case GUI_TIMBRE_SELECT:
-			SendProgramChangeMidiEvent(0,Timbre_index[Group->Current]);
+			/* 双音色库：主弦走 Bank1，先选 bank 再 PC */
+			SendProgramWithBankMidiEvent(0, MIDI_BANK_STRING, Timbre_index[Group->Current]);
 		break;
 		default:
 			break;
diff --git a/midi/midi_send.c b/midi/midi_send.c
index 16016d8..6dce55f 100644
--- a/midi/midi_send.c
+++ b/midi/midi_send.c
@@ -27,10 +27,21 @@ void SendVolumeChangeMidiEvent(uint8_t channel,uint8_t CC)
   SendMidiDataToDreamDSP(midibuff,3);
 }
   
-void SendBankChangeMidiEvent(uint8_t CC)
+/* Bank Select：CC0(MSB)=bank，CC32(LSB)=0。Dream 双音色库：0=伴奏，1=主弦 */
+void SendBankChangeMidiEvent(uint8_t channel, uint8_t bank)
 {
-  uint8_t midibuff[3] = {0xB0 ,0x00, CC };
+  uint8_t midibuff[3] = {0xB0|(channel & 0x0F) ,0x00, bank };
   SendMidiDataToDreamDSP(midibuff,3);
+  midibuff[1] = 0x20;  /* CC32 Bank LSB */
+  midibuff[2] = 0;
+  SendMidiDataToDreamDSP(midibuff,3);
+}
+
+/* 先选 Bank 再 Program Change，避免漏发 Bank Select 落到错误音色库 */
+void SendProgramWithBankMidiEvent(uint8_t channel, uint8_t bank, uint8_t program)
+{
+  SendBankChangeMidiEvent(channel, bank);
+  SendProgramChangeMidiEvent(channel, program);
 }
 
 void SendMidiDataToDreamDSP(uint8_t* buff, uint16_t cnt)
diff --git a/midi/midi_send.h b/midi/midi_send.h
index df1646a..50d835e 100644
--- a/midi/midi_send.h
+++ b/midi/midi_send.h
@@ -2,11 +2,16 @@
 #define __MIDI_SEND_H__
 
 
+/* Dream 音色库 Bank：0=自动伴奏，1=主音色/弦 */
+#define MIDI_BANK_ACCOMP   0
+#define MIDI_BANK_STRING   1
+
 /* MIDI 发送函数 */
 void SendNoteOnMidiEvent(uint8_t Key, uint8_t OnVal);
 void SendNoteOffMidiEvent(uint8_t Key, uint8_t OffVal);
 void SendProgramChangeMidiEvent(uint8_t channel, uint8_t CC);
-void SendBankChangeMidiEvent(uint8_t CC);
+void SendBankChangeMidiEvent(uint8_t channel, uint8_t bank);
+void SendProgramWithBankMidiEvent(uint8_t channel, uint8_t bank, uint8_t program);
 void SendVolumeChangeMidiEvent(uint8_t channel, uint8_t CC);
 void SendMidiDataToDreamDSP(uint8_t* buff, uint16_t cnt);
 void DefaultTask_SendMsg(uint16_t Data1, uint16_t Data2, uint16_t Data3, uint16_t Data4);
diff --git a/midi/midi_tables.c b/midi/midi_tables.c
index 72a35e9..9565163 100644
--- a/midi/midi_tables.c
+++ b/midi/midi_tables.c
@@ -220,8 +220,8 @@ const STRING_MIDI *Chord_Midi_Table[7] =
 const STRING_MIDI *OrganChord_Midi_Table[7] = 
 { OrganMIDI_1,OrganMIDI_2,OrganMIDI_3,OrganMIDI_4,OrganMIDI_5,OrganMIDI_6, OrganMIDI_7 };
 
-/* UI槽位0~4 → MIDI Program Change：24尼龙 / 25钢弦 / 27清音 / 30失真 / 33 Finger贝斯 */
-const uint8_t Timbre_index[5] = {0x18, 0x19, 0x1B, 0x1E, 0x21};
+/* UI槽位0~4 → MIDI Program Change（Bank1）：24尼龙 / 25钢弦 / 27清音 / 30失真 / 34电贝司 */
+const uint8_t Timbre_index[5] = {0x18, 0x19, 0x1B, 0x1E, 0x22};