A torsion output tool has a housing, a motor and a transmission assembly. The transmission assembly includes a first planetary gear train. The first planetary gear train has a first planetary gear carrier, a first level planetary gear, a first inner ring gear disposed outside the first level planetary gear and meshing therewith, and a first central wheel sliding in a direction of a first axis to a first position and a second position. The transmission assembly further has a locking member. The locking member slides synchronously with the first central wheel and only locks the relative circumferential positions of the output shaft and the first planetary gear carrier when the first central wheel is at the first position and only constitutes circumferential engagement with the first planetary gear carrier when the first central wheel is at the second position to achieve a drilling mode and an impact mode of operation for the tool.