Combined with the Ficks second law, the surface chloride concentration of gradient structure concrete(GSC) were calculated for studying the effect of surface layer volume fractions and accelerating period, by conducting the chloride migration rapid test and determining the distribution of chloride. The results show that surface chloride concentration of the GSC is reduced with the increase of volume fractions of surface layer, and finally reaches a stead state; and the surface chloride concentration in GSC gradually grows along with the accelerating period increases, and also reaches a stead state finally. Compared with the specimens of 0% volume fractions of surface layer, that with a higher volume fraction has a faster accumulation rate of chloride on the surface. But when the volume fraction of surface layer exceeds 0%, the accumulation rate of the all specimens is almost equal. At last, the relationship among surface chloride concentration, surface layer volume fraction and accelerated period are put forward respectively based on the existing model.