Based on the great number of standard penetration tests and indoor soil geotechnical test data about the pipe blocking clay in Tianjin port,this paper studied and analyzed the correlation between the standard penetration number and physico-mechanical index of pipe blocking clay by applying the mathematical statistic method.The results show that the regression coefficients in empirical formulas all are above 0.8 with higher reliability.After verification by reliability analysis,the research results provide a feasible method by calculating the physico-mechanical index of pipe blocking clay with the in-situ test index.It helps to cut down the cost for investigation of dredging engineering,provides reference for similar dredging engineering,and owns a higher practical application value.