Abstract: Taking the typical nuclear safety class DCS as an example, the FMVEA technology is used to evaluate the compatibility between functional safety and cyber security. The combination of event tree and risk analysis is used to give functional safety and cyber security coordination solutions, and finally obtain the integrated protective measures of nuclear safety class DCS functional safety and cyber security. The results show that the application of trade-off technology to obtain the cyber security measures can be better compatible with the original functional safety measures. Therefore, the trade-off techniques established in this study can be applied to nuclear safety class DCS cyber security design work.