Abstract: To improve the efficiency, continuity, and weighing accuracy of food packaging, a new multifunctional food portioning machine was designed for mass production, focusing on the mechanical structure and features of traditional automatic portioning machines available on the market. First, by analyzing the food packaging process and applying a combinatorial innovation approach, the overall mechanical structure of the new portioning machine was determined, achieving an innovative overall scheme. Based on this structure, the entire machine was modeled in SolidWorks, and kinematic analysis as well as dynamic simulation of key components were carried out. On this basis, a mathematical model of the bag-loading mechanism was established, and its structure was optimized using the Ant Colony Algorithm, with simulation verification performed in Matlab. Meanwhile, the bag-opening module was functionally improved: as the bag mouth is about to be opened by the bag-loading mechanism, a crank-slider mechanism drives a tool to extend vertically downward along a sliding groove into the packaging bag and translate sideways with the bag-loading mechanism, thereby assisting in the bag-opening process. The results show that the optimized bag-loading mechanism exhibits excellent quick-return characteristics and force transmission performance, while the improved bag-opening method effectively enhances the success rate of bag opening.