After obtaining the results of p53 gene mutation by a silver staining method to polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, P53 protein staining and proliferation cell nuclear antigen (PCNA) index by double-blind method, multivariate correlation analysis two by two showed that PCR-SSCP, P53 positive protein staining and PCNA index had markedly correlation not only in oral precancerous lesions (OPL) but also in primary sites and regional metastatic lymph nodes of oral squamous cell carcinomas (OSCC). This indicated that the nature of the three indexes was the same. After introducing the sex and age of patients which have been proved to be related to the initiation and development of OPL and OSCC according to other researchers and are easy to be obtained in clinics, multivariate discriminatory analysis was carried on and three groups of discriminatory equations were gotten about the pathological grading of OPL and OSCC and metastasis condition of OSCC. The accuracy of these equations was 82.5%, 78% and 80%, individually. This suggests that the equations have applicable potentiality already.