The switch mechanism for the reversible control valve of the pneumatic tool focuses on the switchover bar because of the users' right handed and left-handed issues. The primary feature is to make the switchover bar of the reversible control valve and the speed-adjusting valve to roll in the axial direction, and use the combination of the elastic component to make the combination and position section of the connecting section to position with the valve bar positioning section of the reversible control valve. When force of the connecting section of the switchover bar is pulled toward external trigger, it can release the combination and position section and the toggle switch of the switchover bar can achieve switching. When the toggle switch is adjusted, the repositioning may be restored by using the combination and position section and valve bar positioning section without having to take the parts apart.