A power system of an electric vehicle, comprising: a battery group; a battery heater, connected with the battery group and configured to charge and discharge the battery group to heat the battery group; a battery management device, connected with the battery group and the battery heater respectively, and configured to control the battery heater to heat the battery group intermittently when a temperature of the battery group is lower than a first temperature threshold and a residual electric quantity of the battery group is larger than an electric quantity threshold; an electric distribution box, configured to distribute a voltage output by the battery group; a motor; a motor controller, connected with the motor and the electric distribution box respectively, comprising a first input terminal, a second input terminal and a pre-charging capacitor connected between the first input terminal and the second input terminal, and configured to supply power to the motor according to a control command and a voltage distributed by the electric distribution box; and an isolation inductor, connected between the battery group and the electric distribution box, wherein an inductance L of the isolation inductor is determined by a formula: T = 2 π LC, where T is an equivalent load work cycle of the motor and C is the capacitance of the pre-charging capacitor, characterized in that intermittent heating comprises heating the battery group for one time period and then suspending heating for another one time period, and in that the battery management device is configured to stop heating the battery group in an intermittent heating cycle when any of following conditions is satisfied: the temperature of the battery group is higher than the first temperature threshold; a temperature of any single battery in the battery group is higher than a second temperature threshold, wherein the second temperature threshold is larger than the first temperature threshold; and a continuous heating time of the battery heater is larger than a heating time threshold. a battery group; a battery heater, connected with the battery group and configured to charge and discharge the battery group to heat the battery group; a battery management device, connected with the battery group and the battery heater respectively, and configured to control the battery heater to heat the battery group intermittently when a temperature of the battery group is lower than a first temperature threshold and a residual electric quantity of the battery group is larger than an electric quantity threshold; an electric distribution box, configured to distribute a voltage output by the battery group; a motor; a motor controller, connected with the motor and the electric distribution box respectively, comprising a first input terminal, a second input terminal and a pre-charging capacitor connected between the first input terminal and the second input terminal, and configured to supply power to the motor according to a control command and a voltage distributed by the electric distribution box; and an isolation inductor, connected between the battery group and the electric distribution box, wherein an inductance L of the isolation inductor is determined by a formula: T = 2 π LC, where T is an equivalent load work cycle of the motor and C is the capacitance of the pre-charging capacitor, the temperature of the battery group is higher than the first temperature threshold; a temperature of any single battery in the battery group is higher than a second temperature threshold, wherein the second temperature threshold is larger than the first temperature threshold; and a continuous heating time of the battery heater is larger than a heating time threshold.