The invention discloses a positioning method of an inter-harmonic producing source. The positioning method comprises the following steps: monitoring power oscillation, caused by inter-harmonic current, of all wind power plant inlet wires of a wind power collection station, and computing the amplitude value and the instantaneous value of power oscillation; monitoring power oscillation, caused by inter-harmonic current, of inlet wires of a thermal power plant adjacent to the wind power collection station, and computing the instantaneous value of power oscillation; monitoring phase angle difference vibration between the bus voltage of the wind power collection station and the bus voltage of a thermal power plant adjacent to the wind power collection station, and computing the oscillation amplitude value and the change rate of the bus voltage phase angle difference; positioning the inter-harmonic producing source according to according to the relation among the amplitude value of the power oscillation of the wind power plant inlet wires, the instantaneous value of the power oscillation of the wind power plant inlet wires and the instantaneous value of the power oscillation of the outlet wires of a certain thermal power plant adjacent to the wind power collection station and the relation among the amplitude value of the bus voltage phase angle difference, the instantaneous value of the power oscillation of the wind power plants and the change trend of the bus voltage phase angle difference. The method does not need to design a complex filter, thereby reducing the calculated amount and facilitating practical engineering implementation.