This application embodiment provides a detection apparatus for insulation resistance, and the device includes: partial pressure module, sampling module and treater, the first input end of the direct current side device in the electrochemical energy storage system is connected to partial pressure module's first output, and partial pressure module's second output is connected to the second input ofdirect current side device, and partial pressure module's third output is connected to the ground wire of electrochemical energy storage system. The treater is arranged in controlling the closed of each switch of partial pressure module or disconnection to the circuit connection who triggers among the partial pressure module changes, the sampling module is arranged in gathering the voltage of thesampling resistor under the different circuit connection states of partial pressure module, the treater still is used for: according to the voltage of sampling resistor and the resistance of samplingresistor, confirm the insulation resistance of electrochemical energy storage system. It is thus clear that, realized the detection to the insulation resistance of electrochemical energy storage system.