Abstract: A brief account of C. T. R. Wilson＇ s main contributions and the course of inventing the cloud chamber are given. How he began from the researching of the law of drop＇s forming,improved his experimental apparatus continuously, photographed the tracks of charged particles and provided experimental conformation of the Compton effect are reviewed. Several important factors which made Wilson successes are analyzed.

Key words: C. T. R. Wilson, cloud chamber, tracks, Compton effect