The durability life prediction of the reinforced concrete structure of the existing wharf is faced with the problems of few available analysis parameters，low degree of fit，and doubtful prediction results.We obtain the distribution value of chloride ion concentration in the concrete core sample through on-site sampling tests.Based on the modified chloride ion diffusion model，we carry out the regression analysis using Matlab software to obtain the chloride ion diffusion coefficient，attenuation coefficient，surface chloride ion concentration and other parameters of the test piece，and predict the durability life of the breast wall reinforced concrete structure of the existing wharf.The results show that the prediction results of the parameter setting method are too large，and the prediction results based on the failure probability prediction method are basically consistent with the calculation results of the standard method，which is more consistent with the engineering practice.