In this paper, thetheory and experimental method of self-tuning of prism chromatic dispersion cavity arediscussed in detail. The computer control system for self-tuning is also elaborated. Thistuning method can apply to solid tunable laser. In experiment, this tuning system is usedin Ti: sapphire laser pumped with 532～nm of Nd:YAG mode-lockinglaser. It can realize output of wavelength range from 680～nm to 980～nm.