Establishing a simplified model for ship lock passing，using the stochastic simulation method combining the Monte Carlo method and 2D bin-packing heuristic algorithm，we compute the passing capacity of different ship lock design schemes at different scales，discuss the results for different simulation implementations considering different factors，and optimize the reasonable design scheme. The results show that when using the ship’s first-come-first-served strategy，the lock chamber utilization rate of ship locks of the same width is about the same，and the tonnage index of one-pass ship lock increases as the ship lock chamber length increases. When the ship selection service strategy is adopted，the tonnage index of the first pass is higher than the calculated index of the first-come-first-served service strategy，and the average number of times to ship lock the gate shows a single increase trend after the ship lock reaches the busy state. The L4 ship lock design scheme shows advantages in ship type adaptability，pass ability，service quality level and other indicators. When calculating the pass capacity on the basis of the random simulation of the ship lock，it is necessary to reasonably determine the specification formula parameters in conjunction with the actual operation of the ship lock