The invention relates to an unloading circuit for DC motors, which is characterized in that the unloading circuit includes a power supply, a voltage regulator circuit module, an overvoltage judging module, an electronic switch module and an unloading resistor R3; the positive electrode of the power supply is connected with the voltage regulator circuit module, the overvoltage judging module, one end of the unloading resistor R3 and the positive electrode of a DC motor; one output end of the voltage regulator circuit module converts and stabilizes the voltage of power obtained from a DC bus andoutputs the power to the overvoltage judging module, and the other output end of the voltage regulator circuit module outputs a reference voltage signal to the overvoltage judging module; and the output end of the overvoltage judging module is connected with the electronic switch module in order to send a switching instruction to the electronic switch module. The whole unloading circuit can be integrated on a small circuit board, and can be directly connected in parallel between the positive and negative power supply terminals of the motor without an additional auxiliary power supply.