The invention relates to a substrate position identification processing method for an image identification system of a laser scribing machine. The method comprises the following steps of performing binary processing on an acquired whole image; performing edge detection on a Mark point of the image to obtain horizontal and vertical central point lines of a cross; detecting a central line of the Mark point, transforming central points on the central point lines of the cross into sine lines of a rectangular coordinate system parameter space, transforming solving of a straight line into solving of polar coordinate parameters of an intersection point between the sine lines, and obtaining polar coordinate parameters of the horizontal line and the vertical line of the cross; and obtaining polar coordinates of an intersection point of the cross according to the polar coordinate parameters of the horizontal line and the vertical line of the cross. The method is high in identification precision and high in reliability, and can be suitable for a device required to be subjected to image identification processing, such as the laser scribing machine, a laser cutting machine or the like.