In order to explore the response characteristics of electric supercharger, the changing laws of electric parameter, speed and inlet and outlet pressure were researched under dynamic conditions. The test results proved that the phase current could change with the order of millisecond and showed the step response while the target speed abruptly increased. Besides, speed and pressures changed with the order of second. The effective values of phase currents had similar response laws under different speed ranges so that the partial coincidence of phase voltage, speed and pressure variation curve occurred during the acceleration. The speed and pressure would overshoot when the speed increase range is large, which indicated that the electric supercharger should be regarded as a second-order or high-order nonlinear system. The speed change range would affect the dynamic changing laws of phase current during the deceleration. The response time of deceleration was significantly larger than that of acceleration in the same speed change range, hence different control strategies should be adopted under the two conditions. In addition, a dynamic experimental study was carried out under the special unstable working condition of electric supercharger and significant surge frequency components could be found within the effective value of phase current, the speed and the pressure. However, it could not be found within the instantaneous value of phase current.