The utility model discloses a DC charging and changing station insulation detection apparatus. The apparatus is characterized by comprising an upper balance branch and a lower balance branch serially connected between an anode bus and a cathode bus of a charging and changing station DC system. An upper imbalance branch and a lower imbalance branch are respectively connected to the upper balance branch and the lower balance branch in a parallel way. Corresponding balance circuits or imbalance circuits are serially connected to the upper balance branch, the lower balance branch, the upper imbalance branch and the lower imbalance branch. A corresponding control switch is serially connected in each branch. A connection point between the upper balance branch and the lower balance branch is used for ground connection. The apparatus further comprises a data detection processing unit used for detecting the voltages to earth of the anode bus and the cathode bus. The DC charging and changing station insulation detection apparatus adopts a mutually switching method among the balance circuits and the imbalance circuits. The detection apparatus is accessed to the DC system for monitoring purposes. The system safety is guaranteed through insulation leakage current detection. Human electric shock risks can be prevented. The system fault generation probability can be further lowered.