您需要转义反斜杠字符. 每个反斜杠使用\\而不是\

you need to escape backslash character. use \\ instead of \ for every backslash,

subprocess.run("C:\\Program Files (x86)\\Arduino\\arduino.exe",shell=True,check=True)

或者您可以使用原始字符串文字

or you can use raw string literal,

subprocess.run(r"C:\Program Files (x86)\Arduino\arduino.exe",shell=True,check=True)