we want to analyze user access activity on internal forum, to prevent abnormal user crawl our sensitive pages, so I want to collect user access log, if Discourse have user access log？ where I can find it?
Sounds like that the “we” party first needs a good talk with the “yours” privacy and ethical committee. And of course, do this on a self hosted Discourse instance with a clear privacy policy about this. The only public info you can get here (I guess) is on the about page.
There are built in controls to rate limit crawling.
If you have the data explorer plugin you can see who has seen what pages.