Is there any new nikon professional cameras going to be launch?

I'm going to buy D 300s.

What is your background in photography, and what do you want to shoot with it?

Frankly, you sound a lot like a beginner, and you seem to believe that by buying an expensive camera you'll nearly automatically take professional grade photos. That is not so. Someone who has grown out of his or her entry level or prosumer grade DSLR wouldn't call a D300s a "professional camera," that term is typically used by people who are entirely new to DSLRs.

I'd recommend an upper entry level grade camera at first, or a D7000 if you want to spend a bit more money for a prosumer grade one. Also keep in mind that the lens is more important than the camera body.

You won't get better photos with a D300s than with a D5000.

Anyway, to specifically answer your question, the successors to the D300s and D700 (not to be confused with the D7000) will likely be announced within the next few months.

The big announcement day is Aug 24th. The latest rumor is that no new DSLRs will be announced, only some new Coolpix cameras. But rumors are rumors, and Nikon can be a bit sneaky about it. There may be another announcement in Sep, but that is just yet another rumor.