Abstract: The DCS overall structure of CRP1000 nuclear power plant was introduced. Based on the RPC, the signal interface character and signal processing mechanism on the key root were analyzed. By the power loss analyzing of RPC, the RPC loss power may lead reactor trip signal from anticipated transient without scram (ATWS) system. The results indicate that it is necessary to search DCS cabinet power loss analysis. Optimizing and assigning the main waterflow signals can avoid trigger reactor trip signal by mistake. The DCS cabinet power loss analysis can optimize the I&C (instrumentation and control) design and increase the nuclear plant’s reliability.