Objective To study the infection of HPV16/18 and the presence of multiple oncogene on the carcinogenesis of cervical squamous carcinoma.Methods Immunohistochemical method was used to detect E6?PCNA?p53?p 21ras and c myc protein expression in 19 cases of chronic cervicitis?40 cases of cervical intraepithelial neoplasm (CIN) and 70 cases of invasive cervical carcinoma.Results A high positive expression rate of E6?PCNA?p53?p 21ras was found in CINⅢ and invasive cervical carcinoma which c myc positive expression rate was significantly lower than chronic cervicitis?CINⅠ and CINⅡ.Conclusion HPV16/18 infection and the abnormal expression of PCNA?p53?p 21ras ?c myc may play an important role in the carcinogenesis of cervical squamous carcinoma.