Based on characteristics of the description language in the emergency plan, this paper designs an emergency response plan complexity evaluation system with the evaluation methodology for the plan’s maneuver- ability. By using the B/S construction and with PHP, APACHE and MySQL, the complexity evaluation system has been realized through working on system requirements analysis and on its conceptual, logical and physical design. The system provides a human-computer interaction interface where quick searching, viewing, judging, adding, amending and deleteing can be done. It supports the experts to improve the emergency plan by decomposing the plan’s mission, analyzing the basic sub-task’s complexity and achieving the quantification of the plan’s complexity.