can i have H4 visa while having stamped H1B

I have stamped H1B visa valid untill Dec-16. My spouse may travel to US in H1b soon .Can i apply for H4 as now and travel in H4. In this case, will the H1B visa get cancelled.If i travel to US in H4 visa what are the chances to work there.

There is a possibility that the officer would cancel the H-1B visa stamp w/o prejudice when approving the H-4 visa.

If you enter US on H-4 (irrespective of whether H-1 visa stamp is canceled or not), you can still work after applying for COS from H-4 to H-1. This can done with same employer, or a different one. Cap-exempt petition needs to be filed if you want to move to a different employer or want an extension.