1、開啟PS，選中alpha通道，右鍵【複製通道】。

https://iknow-pic.cdn.bcebos.com/0df431adcbef7609df097e4d20dda3cc7dd99ee6

2、在彈出的【複製通道】對話方塊裡，目標欄目文件裡選擇【新建】。

https://iknow-pic.cdn.bcebos.com/42166d224f4a20a41c7ddb159e529822730ed085

https://iknow-pic.cdn.bcebos.com/96dda144ad3459823cab024002f431adcbef843b

https://iknow-pic.cdn.bcebos.com/0b46f21fbe096b6390cab98202338744eaf8ac15

https://iknow-pic.cdn.bcebos.com/d1a20cf431adcbefe5fa99d4a2af2edda2cc9f12