The present invention relates to a power tool monitored by tracking a motor current and control methods thereof. The present invention is mainly about a microprocessor electrically connected to a motor through a drive unit and a current detecting-and-converting module. The microprocessor receives an AC synchronizing signal, and sends a first control signal to the drive unit according to the AC synchronizing signal to drive the motor. The current detecting-and-converting module detects and converts the motor current and output to the microprocessor, thereby the microprocessor detects a per unit time current which is converted into a corresponding pressure value, and then the microprocessor sends a second control signal to the drive unit according to the pressure value to control the operation status of the motor. By detecting and tracking the per unit time current, the purpose of load monitoring and motor protection can be achieved.