Abstract: The SP immunohistochemical method was performed On 65 cases of dysplastic gastric mucosa to detect expression of PCNA (PC10). P53 (Do-7) and C-erbB-2 (PAb1) proteins. The results showed that the mean PCNA indices were 22.34%, 32. 58 % and 46 .08 % respectively, and there was a significant difference (P＜0.01)between these Varied groups, the mean PCNA index was increased with the progression of the pathologic grade in dysplastic gastric mucosa, there were significantly positive correlation (r=0.966, P=0.0005) between the pathologic grade andPCNA index; Abnormal expression of C-erbB-2 and P53 proteins were not observedin grade Ⅰ and Ⅱ dysplastic gastrlc mucosa, While C-erbB-2 was found in 7 of the 25 grade Ⅲ (28%), and P⁵³ in 8 of the 25 grade Ⅲ (32%) dysplastic gastric mucosarespectively. The signlficance on expression of PCNA index, P53 and C-erbB-2 proteins are also discussed in dysplastic gastric mucosa.