Now days AdSense account is difficult to open. Is there any AdSense alternative avaiable working like AdSense? I am very very eager to know about alternative.

Try Media.net (It's Yahoo!/Bing's alternative to AdSense). However, truth be told, no other PPC network is going to make the same kind of money that AdSense does. And if you can't get into AdSense, you most likely won't be making much money elsewhere either. (Unless it was because you got banned from AdSense for fraudulent clicks.)

You can always try 7search, but adsense is the best.

If I don't have any website in that case how can I earn by pay per click.

amazon ads - you don't have to be approved, however if your site isn't up to snuff that site will be blocked after a week or two.

Qadabra is really great alternative of Google Adsense. Thanks

As far as i know , the Adsense is one of the best PPC network because it is not only offers PPC but they also offer CPM ads. The earning potential in Adsense is much higher. However, Google is getting very strickt day by day not in terms of approving the adsense account but also in terms of paying you money.