A circuit structure applied to a motor and enabling upgraded MOS transistor heat dissipation ability is disclosed. The circuit structure includes a motor driving unit and a signal processing unit. The signal processing unit is connected to the motor driving unit for maintaining a first and a third switch of the motor driving unit at a constant turn-on voltage and boosting turn-on voltages of a second and a fourth switch of the motor driving unit, so as to effectively upgrade the heat dissipation ability of the first, second, third and fourth switches.