In this paper, the developed courses and important achievements of atmospheric sciences in the 20th century are reviewed. The important progresses and academic achievements got in the studies on atmospheric sounding technology, atmospheric general circulation and large-scale dynamics, numerical weather forecast and numerical simulation of atmospheric general circulation, atmospheric physics, meso-and small-scale meteorology, atmospheric environment and atmospheric chemistry, middle atmosphere, dynamics of climate system, climate prediction and global change etc. for recent 100 years in the 20th century are systematically reviewed. Moreover, the prospects of the studies on atmospheric sciences in the early 21st century are also made in this paper.