The invention provides a power tool (100) used for indicating the reached torque limit for the operators. The tool comprises a driver circuit (312) used for producing the electric motor interface drive signal, an electric motor interface circuit (314) connected to the electric motor (316) according to the electric motor drive signal connecting to the electric motor selection, a torque limit signal generator (336) used for generating the torque limit signal, a electric torque limit signal generator for generating the corresponding torque limit signal with the electric motor, and a micro controller (310) used for comparing the electric motor torque signal to the torque limit signal and responding to the torque signal equal to or more than the torque limit signal to generate the torque limitindicating signal, thereby the driver circuit vibrates the electric motor to warn that the operator has reached the torque limit.