The invention discloses a device for detecting the inductance of a quadrature-direct axis, which comprises a power analyzer, a motor controller and a tooling device used for fixing an outer rotor of adetected outer rotor motor, wherein the motor controller is connected with an upper computer, a DC power supply, a potentiometer and the detected outer rotor motor, the potentiometer adjusts the voltage and current amplitude of a driving signal outputted by the motor controller, the motor controller converts steady direct current provided by the DC power supply into an alternating-current drivingsignal required by driving the detected outer rotor motor according to an instruction of the potentiometer so as to control the start, operation and stop of the detected outer rotor motor; the motorcontroller can change the frequency of outputting the alternating-current driving signal according to the setting of the upper computer; the power analyzer is connected with the motor controller and the upper computer so as to detect the voltage amplitude, frequency and current amplitude of the driving signal of the motor controller, record waveform data, transmit the recorded waveform data to theupper computer for storage and then outputs the waveform data for display. The device does not produce torque when detecting inductance parameters of the motor, and simplifies the detection tooling.