Now a day I am working on my twitter account and increase my follower for increasing traffic of my adsense blog. My question is it have any bad effect on adsense or not.
You will get more traffic , but not natural from Search engine, It's referral traffic..... Not to sure whether have any bad effect on adsense or not. Just common sense if google found that you got a lot of traffic, but most of the visitor didnt convert very well to be a prospect buyer ( adwords /advertiser ).
If you gather a lot of followers and Tweet about each post then you should get a few click through to your blog and subsequently onto your ads. It's not bad traffic, because it's clearly targeted to your blog, but it probably won't increase your earnings that much. In my experience people use Twitter because they're in a hurry and they don't spend much time following Tweeted links. To make any real difference you would need thousands of followers.
No way! Google can't really tell where your traffic is coming from as long as the clicks look valid. Plus twitter followers doesn't guarantee that you'll get any clicks whatsoever.