Hi i recently saw by sharing our cpu and gpu we can earn btc throw nicehash.But my cpu utilization is always 100%. is it profitable or it will generate any problem.
CPU mining is hobby mining. That means that you will get less money of it than the cost of the electricity you'll use.
I didn't personally use their miner, but there are ways to make the normal (command line) miners to run on low(er) priority. The CPU usage will still be 100%, but at least you'll be able to use it while mining. If this doesn't work with nicehash miner and you want to also use the computer for this and that, I suggest you do some research and get another miner program. Then you can mine on any pool or multipool you want.
As others said: long time 100% utilization of CPU is OK only if you have proper cooling. So if you use laptop, I'd advise you to stop mining. Desktop is OK.
I don't know if you also mine with the GPU - it works only with pretty powerful ATI and GeForce cards - but that can be profitable (if not laptop), but you can calculate it well since GPUs eat pretty much electricity.