A laser marking machine includes a support portion, a laser marking device fixed on the support portion, a control chip and a fixing mechanism fixed on the support portion. The fixing mechanism includes a support board configured for supporting a workpiece, and four positioning blocks moved, and four motors being able to control the four positioning blocks to slide in the support board. The fixing mechanism further includes at least two position detectors. The two position detectors are able to position detector a distance data of the workpiece deviating from a center of the support board along X and Y axes, and transmit the distance data to the control chip. The control chip analyzes the distance data to control the four motors to respectively drive the four positioning blocks to slide in the support board until the workpiece is centered on the support board.