The management of the stack yard of bit dry bulk terminal is an important issue. Based on the stochastic service theory, we carry out a study on the dynamic changes of yard pile-bit, analyze the theory of the dynamic change of yard pile-bit, and establishe a yard pile-bit dynamic mathematical model by gridding the continuous space of the yard. On this basis, we establish a simulation model of the coal terminal logistics system which has a fine description of the dynamic change of the yard pile-bit. Moreover, we make a simulation test of an actual professional coal terminal, which verify the accuracy and applicability of the model.