Hi tiebiehao,

I'm sorry, but I don't follow you. I guess you'd like to disable the Forum and Topic Viewers Tracking, right? 

If so, all these information are controlled by five options, please check them out:

1. Track Forum and Topic Current Viewers (Forums > Settings > Features Tab)
2. Display Forum Current Viewers (Forums > Settings > Forums Tab)
3. Display Topic Current Viewers (Forums > Settings > Topics & Posts Tab)
4. Display Topic Recent Viewers (Forums > Settings > Topics & Posts Tab)
5. Display Admins with Topic Viewers (Forums > Settings > Topics & Posts Tab)