A clamping mechanism includes a driving assembly, a gear assembly and a clamping assembly. The driving assembly includes a driving gear. The gear assembly includes a first slave gear, a second slave gear and a connecting rod which is coupled with the first slave gear and the second slave gear. The first slave gear meshes with the second slave gear. The clamping assembly includes a first clamping member and a second clamping member, which are coupled to the first slave gear and the second slave gear respectively. When the driving gear rotates, the first slave gear and the second slave gear would rotate in opposite directions to enable the first clamping member and the second clamping member to move toward or away from each other, thereby clamping or releasing a workpiece.