Abstract: The difference of internal stress caused by different types of polycarbonate(PC) test specimens and its parts, different mold temperatures and different solvent resistance were characterized through a series of soaking experiments at different components and solvent concentrations. The effect of annealing process on the improvement of internal stress of the parts was verified, and the effects of stress and mechanical properties of the parts were quantitatively measured and analyzed. Furthermore, the solvent stress cracking mechanism of the parts were analyzed and discussed. The results indicated that CCl4 was not suitable to characterize the difference of stress and solvent resistance of PC due to its high corrosion, and however a mixture of toluene and n-propanol was suitable as a solvent for this characterization. The formation of PC/PBT alloys could effectively improve the resistance to solvent-induced crack of PC. The difference of mold temperature could give a more than 30 % influence on the numbers of stress crack of PC. The stress cracking problem of PC parts could be solved effectively by annealing at 110 ℃ for 2 h, and meanwhile, theirstrength was not reduced significantly.