Based on the research results that the chloride ingression in concrete is influenced by many factors, the model for service life prediction of marine concrete is proposed, with the Fick's second law taken as the basic model, and introducing correction factors of exposure time, chloride binding, environment temperature, stress and crack conditions, and combining reliability analysis method. Based on the model the calculation software SLPMC is established. And the service life of some marine concrete constructions in designing is predicted using the SLPMC on the results of this research.