Abstract: The truck assembly line is one of the most important phases of a vehicle manufacturing. One of the most key factors to make the enterprise more efficient and competitive is how to find and eliminate the bottleneck of the line in time. Based on the current production status of a truck manufacturing enterprise, a whole assembly line is modeled by the computer simulation software named ProModel. The parameters of the line, such as utilization of workstation, cycle time, work-in-process (WIP) etc., are obtained, and therefore, the bottlenecks of the line can be identified. Simulation results can help the factory managers to make better capacity plan and inventory control and improve the production efficiency.