Abstract: Due to 3.3 kV power supply, 6 kV and 10 kV high-voltage electrical universal application in the coal mine underground, and underground complex and changing environment, it had extremely high performance requirements to 3.3 kV and above coal mine explosion-proof electrical protection. The article elaborated checking device of protection performance from a coal mine explosion-proof electrical products testing and inspection angle, which ensured underground electricity and personal safety.