Technology dififusion is a basic methed to solve teclinical backword of software mindustry, which characters with"S"sharp on diffusional paty. Network effect is a busic characteristics when network economical age,and affects technolog diffusion at different degree. Based on industry construetural analyses model of constracture-action-effet, The technology diffusion Theory of network effect on soffware industry is explained from theory, and proposed some suggestion for goverment and corporations.