You need very high volume traffic to get AdSense API. I don't think you have that kind of traffic otherwise you won't be spending time here asking questions. If you have high volume traffic, Google will approach you. I don't remember how much traffic, but I think it is at least one million visitors (or page views).
u dont need to worry about my traffic,the question is not about my site. im just need more information about adsense api for people who have use it, as i know dp is one of them
AdSense API is Google's advertising sharing solution for user-generated content sites. Web hosting for its users, web publishing, writing a blog or social networking applications to create their own Web content developers, Web site, AdSense API is the ideal solution.