Nuclear safety system is investigated by the airbag in which the earthquake- resistance performance is manifested. Most degrees' earthquake could be compromised, which is different from the conventional earthquake regulation where the fixed regulation as 6.5 or 7.0 in Richter magnitude scale is used. Assuming some variable in the simulations, the volume is obtained. In the simulations, at 307th day (at this time, 2,601.94 10,000 pascals), the volume is 9.58647 m3. So, one side of the airbag is proposed as the size of 2.124318 meters. The perfect safety system for the earthquake is constructed in the nuclear power plants (NPPs). This skill could be applicable to the other kinds of industry for the earthquake protections.