A positioning machine includes a base, a support portion mounted on the base for supporting a workpiece and a first positioning mechanism received in the recessed portion. The base defines a recessed portion. Two sidewalls of the recessed portion respectively define a pair of first tracks. The first positioning mechanism includes a first motor, a first coupler, a first positioning block, a first screw rod, and a first nut movably mounted over the first screw rod and fixed to a low surface of the support portion. The first coupler is forced by the first motor to drive the first screw rod to rotate to drive the first nut to move along the first screw rod, causing the support portion to be moved along the first tracks, and the workpiece to be moved in a predetermined position relative to the base.