Mr. Qian Xuesen is the founder of China's systems engineering theory. According to the experience of China's aerospace industry, he summed up the systems engineering methods with Chinese characteristics, and further developed the theories of system science architecture and meta-synthesis method, etc. By reviewing development process of Qian Xuesen's thought on systems engineering, we can not only understand his thought on systems engineering correctly, but also find out guide and methods for developing SOS engineering.