Pitting corrosion damages seriously the structure strength of port facilities. To estimate the lifetime of port facilities, a new lifetime distribution model of port facilities with pitting corrosion of stochastic processes is proposed. Pitting corrosion can be considered as a combination of two physical processes: pit initiation process and pit growth process. The pit generation process is modeled as a non homogeneous Poisson process. The pit growth process is represented by a gamma process. A lifetime distribution model is derived based on the combined stochastic processes. Finally the proposed models are tested and simulated. The results indicate that the proposed model is feasible and valid for estimating the lifetime of port facilities.