Aiming at the problem that the research on the reliability assignment method of the shore-landing unloading system is not perfect and the reliability assignment results need to be optimized, a reliability assignment method based on the improved whale optimization algorithm (IWOA) was proposed. According to the parallel and series logical relationships existing among various tasks of the shoreline unloading system, a reliability assignment model of the unloading system was constructed, and reliability allocation method based on the IWOA was designed to complete the relia-bility allocation of tasks. The simulation method was used to evaluate the assignment results of the proposed method, and the reliability assignment method for shore unloading operation was verified. The simulation results show that the optimal reliability of the system is 0.975, which can enhance the task reliability allocation capability of the shore unloading operation system.