the links on a page will rotate everytime the page is loaded, so I guess it may be a little easy for search engine to filter out these kind of links, for example, record this link first, 5 days later, if these links are still there then count them, otherwise just ignore these links do I worry too much? Or is there any solution here ?
It would be possible to make them semi-static, but then it defeats the purpose of being an ad network, now doesn't it? Do you want your AdSense ads to always display the same ad?
It would require an awful lot of resources on each search engine's part to re-spider every page that shows new links that often.