Abstract: In the context of increasingly fierce manufacturing competition and increasingly complex production tasks, accurate production capacity evaluation has become crucial for enterprises to maintain competitive advantages and enhance production efficiency. However, traditional man-hour measurement methods demonstrate significant limitations in addressing complex manufacturing environments,particularly in handling dynamic disturbances during production processes. This study proposes and develops a task-driven production capacity evaluation simulation system for complex manufacturing environments. The system integrates functional modules including production line definition, order management,capacity analysis, simulation operation, and capacity evaluation. It calculates theoretical effective capacity through analytical methods and estimates practical capacity via order-driven discrete-time simulation, thereby achieving production simulation and capacity evaluation under non-ideal conditions. A case study conducted in a machining factory of a manufacturing enterprise demonstrates that the proposed method and system can more accurately evaluate production capacity and calculate equipment utilization rates in non-ideal environments, showing enhanced flexibility and reliability compared with conventional approaches.