The CloudSat and CALIPSO satellites were launched into space from Vandenberg Air Force Base in California at approximately 6:02 a.m. EDT on April 28, 2006, begi nning a mission to study clouds from orbit. In this paper, close attentions are paid to a new type cloud detecting satelliteCloudSat. The preceding sections g ive a general overview of the detecting instruments embarked on CloudSat and the “ATrain" constellation. The main products of CloudSat and the ways to get th em are especially described, and then two samples of cloud detection by CloudSat for different kinds weather of synoptic situations are displayed. At last, the applications of CloudSat productis to some aspects of weather or climate in futu re are discussed.