@Brajeshbasu,
Any exercise is good for your cardiovascular system.
The argument for morning exercise is more about fat burning and muscle building. The idea being that exercising before breakfast means you're using stored energy (fat) and that eating protein immediately after exercise allows for quick muscle repair/building. Also getting your metabolism hyped up at the start of the day has some pluses, as opposed to night, particularly late at night. We are talking relatively small differences though.
So yes, you may exercise at night with my blessing.