Abstract: In order to improve the packaging efficiency, continuity, and weighing accuracy of food, a new multi-functional food subcontracting machine has been designed for mass production, based on the mechanical structure and characteristics of traditional automatic subcontracting machines on the market. Through analyzing the process of food packaging and adopting the method of combined innovation, the overall mechanical structure of the new subcontracting machine has been determined, realizing the innovation of the overall scheme. According to the overall structural plan of the new subcontracting machine, the modeling of the overall model has been completed through SolidWorks, and the motion analysis and dynamics simulation have been performed on its key components. Based on the mathematical model of the bagging mechanism, the optimization of its structure has been carried out through the ant colony algorithm, and the simulation analysis has been conducted using Matlab software. The results show that the bagging mechanism has good quick-return characteristics and force transmission performance. The function of the bag opening module has been optimized. When the bag opening is about to be opened by the bagging mechanism, the cutter is pushed by the crank-slider mechanism to move vertically downward in the chute to enter the packaging bag, and meanwhile, it moves horizontally towards the sides of the packaging bag with the bagging mechanism to assist in opening the bag. This bag opening method has improved the success rate of bag opening to a certain extent.