Abstract: Durability deterioration caused by chloride penetration is one of the most serious problems of marine concrete structures in chloride environment. This paper explores the application of empirical durability deterioration model to marine concrete structures, utilizing the in-situ test data from durability inspection and assessment reports in South China. This paper discusses the environmental load (C_s) model of concrete structures subjected to chloride penetration, and determines the probability distribution, mean and standard deviation of C_s by regression analysis based on the Fick's Second Law. Finally, this paper adopts a Monte Carlo Simulation program to compare the obtained environmental load model with existing ones, and discusses the influence of environmental load model on durability analysis.