The invention discloses a direct-current motor-driven wrench, which comprises a shell, a power supply device, a direct-current motor, an ordinary gear train reduction gear, a planetary gear train reduction gear and a wrench main body, wherein the direct-current motor is arranged in the shell and is connected with the power supply device; the ordinary gear train reduction gear is driven by the direct-current motor and is connected to the shell; the planetary gear train reduction gear is driven by the ordinary gear train reduction gear; and the wrench main body is connected with the planetary gear train reduction gear. The direct-current motor-driven wrench also comprises a sensor, an information processing device and a display device, wherein the sensor is used for measuring the revolving speed of the direct-current motor; the information processing device comprises a torque calculation module, a storage module and a control module, wherein the torque calculation module is connected with the sensor and the display device; the storage module presets a reference current value; the control module is used for measuring the practical current value of the direct-current motor and comparing the practical current value with the reference current value; and when the practical current value is larger than the reference current value, the control module controls the direct-current motor to stop rotating. According to the arrangement, the direct-current motor-driven wrench disclosed by the invention can provide bigger torque force, and a corresponding torque value is set according to an installation requirement.