A combination electric tool includes a main body and at least one working part drivable via and separably attachable to the main body. The main body includes an electric motor and a control circuit with a signal recognition module having a microcontroller. The working part includes an identification module, the signal recognition module and the identification module being communicable such that the microcontroller can recognize the working part. A control method includes attaching the main body to the working part; judging which kind of working part is attached and selecting corresponding preset programs; sampling a working parameter value of the electric motor; comparing the sampled working parameter value of the electric motor with a corresponding preset value, and judging whether the electric motor is at an abnormal working state; and if yes, powering off the electric motor, and if no, returning to the previous step.