Ok, I figured it out by myself

it is a error when OpenStudio export IDF file

for eaxmple:

I have equipment list like this:

four equipment in list, but two exhaust fan shouldn't be listed in heating or cooling sequence. So when it export IDF file, it does skip two fans, but the index for the fourth equipment are export to IDF file:

To figure it out, just put these two fan at the end of list, the index transferring should be fine.