The work aims to design a location system for cutting of high-precision bag making machine based on machine vision, aiming at the problems of burrs and wastes in the traditional cutting process of fillet packaging bags. LED backlight, low distortion lens, CMOS black-and-white camera and industrial personal computer were used to build the hardware platform of the vision system. In the Visual Studio development environment, the vision software was programmed based on OpenCV function library. The image edge was detected based on the least square method for the camera calibration. The package fillet contour was extracted as the feature information. The system took the feature information as the matching template to accurately locate the fillet position, obtain the sub-pixel level point, and finally control the servo system to perform error compensation and bag cutting. The location algorithm could achieve precise location of fillet in 16 ms, and the absolute error of location was less than ±0.02 pixels. Featured by fast operation speed and high precision location, etc., the location system based on machine vision effectively improves the traditional bag making process, and can meet the production requirements.