A drive mechanism for a lock comprises a linear-moving sleeve (1), a conversion spring (2) and a rotating transmission component (3). The rotating component (3) is inserted into the linear-moving sleeve (1) that moves along the rotating component (3) in an axial direction. The conversion spring (2) is fitted onto the rotating component (3). The linear-moving sleeve (1) has symmetric protrusions (11). The rotating component (3) comprises an end (4) and a rotating bolt (5). The rotating bolt (5) is plugged into the clipping end (4). The conversion spring (2) has two curved ends (21) which are inserted into the groove (51) of the rotating bolt (5). The conversion spring (2) rotates in conjunction with the rotating of the rotating bolt (5) and the rotation movement is converted to linear movement along the rotating bolt (5).