Emergency exercise is a practical activity that simulates emergency response to test the effectiveness of emergency plans, the completeness of emergency preparedness, the adaptability of emergency response capabilities, and the coordination among emergency personnel. China's nuclear safety guidelines and other documents require nuclear power plant operating units to conduct emergency exercises regularly to maintain and enhance their emergency response capabilities. Currently, nuclear accident emergency exercises generally adopt a large-scale, full process on-site practical operation approach, which is costly and lacks effective tabletop exercise tools to support high-frequency daily exercises and drills. This study proposes a system for tabletop exercise of emergency response to nuclear accident, including a database, human–computer interaction module, scenario management module, exercise initiation module, exercise control module, robot simulation module, emergency response module, message push module, exercise visualization module, exercise record and review module, etc. With the support of this system, the complete process of data preparation, setting of exercise information, launch of exercise, intermediate process of exercise, termination of exercise, exercise recording, and exercise review can be accomplished. Through practical testing, the above system and method can achieve full-process automation of tabletop exercise for emergency response to nuclear accident. It can achieve a hybrid simulation mode of “real personnel + robots” (emergency response of exercise personnel and simulated emergency response of robots). The system and method support manual intervention based on automatic exercise throughout the entire process; and also support recording and reviewing the exercise process.