A leakage current detection circuit includes a first resistor located on a positive direct current bus, a second resistor located on a negative direct current bus, and a detection processing circuit separately connected to the first resistor and the second resistor, where the first resistor and the second resistor are located on a trunk circuit in a system including the positive direct current bus, the negative direct current bus, and a load, and the detection processing circuit is configured to detect a current flowing through the first resistor, detect a current flowing through the second resistor, and determine a difference between the current flowing through the first resistor and the current flowing through the second resistor as a leakage current.