I have just joined into the bounty program, please show me some good bounty! thank you very much 
If you're looking for bounty campaigns, you can go to bounties section. There's a lot of good bounties in there, but there are also some bounties that are scam. And if you're really interested to participate in bounties, you have to level up first your rank, because newbies are strictly prohibited to participate in any campaign including bounties.
That is not entirely true. Yes, most campaigns on this forum need you to have above Newbie level, but I have personally seen a few that lets Newbies participate. Also, even if you have no account here above Newbie, you can participate in blogging bounties or youtube bounties. Create your own content, if it is really good you get good readers and audience. You get paid for that, regardless of your BCT rank. And there are even other bounties, like email lists, and social media like FB and Twitter.