A multi-process billet cut-to-length control method can achieve the cut-to-length of a multi-process billet by arranging an image information detection and control hardware system and adopting a system initialization process and an automatic process detection and control program, wherein the image information detection and control hardware system comprises an image sensor, a signal processor, a controller and a cutting machine; and the system initialization process comprises three steps namely step 1, calibration of images, step 2 design of an image grid, and step 3, establishment of an image background database. The automatic process detection and control program comprises the following six steps: step 1, setting length value of a billet to be cut, step 2, setting an interval time for image acquisition, step 3 acquiring images and correcting distortion of the images, step 4, performing perspective transformation on the images, step 5, identifying and tracking a billet head, and step 6, cutting the billet by the cutting machine. Once the billet head is identified in any position of an image data field, all the other image data fields on the right side of the image data field can be confirmed as background images; and by adopting the method, the entire operation time can be greatly reduced, and the cutting accuracy can be controlled within +/-5mm.