Shown in the following picture, I want to execute two scripts after router can’t ping http://www.baidu.com,I have tried several signs like comma, colon, both can’t work. thanks

You can only specify one script.
To work around that issue, make a script that calls the other two scripts:
/system script run [/system script find name=firstScript]
/system script run [/system script find name=secondScript]
And call it from netwatch.
I suggest should amend it, because nesting easily make confusion and redundant.