After introducing the new low-voltage protective electrical apparatus—Control and Protective Switching Device (CPS), there came to the importance and social benefits of its reliability. According to the study on CPS’s operation characteristics and failure modes, along with the current national standard and related industry standard, the two reliability indexes were proposed to measure CPS’s reliability for the first time, and the reliability compliance test plans were also provided. All the study did provide a reference for the reliability research work of CPS.