Hi Lal, we would be more than happy to try to help you, but we need a lot more info than you gave in your initial post. For example, what program are you using, what color space are you working in, do you have "Soft Proofing" turned on, do you experience this effect only with certain colors, is this problem occurring in files where you use advanced blending modes or have moved the opacity or blendIF sliders, ect., etc.
Your question reminds me of a guy who walked into an auto repair place as I was waiting for my car, and the only thing he could say was that "my car goes too slow". The guy behind the counter very courteously smiled and said, "we'll check it out". Unfortunately, since we don't have that possibility on an internet forum, we need more info from you.
Cheers,
Tom M