Abstract: Abstract: Canning technique is a matured method for long term storage. This method is often used to kill microorganisms and spores by thermal process. Thus, the canned food is widely accepted all over the world. Thermal sterilization is a process used for sealed packaging food, which requires heat and time in order to reduce the number of microorganisms to a specified quantity range. In order to guarantee the safety of canned food during the long-term storage, excessive sterilization is frequently-used in the production process. Consequently, the quality loss of canned food is very serious. Therefore, the optimization of sterilization for canned food is considered as a major research subject in food science field. Compared with the traditional constant retort temperature (CRT), the recently appeared variable retort temperature (VRT) technique is recommended as an effective method to decrease the loss of food quality. It is attributed to the fact that the VRT sterilization procession can be used to slowly decrease the temperature to the slowest heating point. In this case, the serious quality loss caused by partial overheating can be effectively reduced. Gradient heating-up, an important variable retort temperature method, is widely studied in the world in recent years, which is also the main focus of our optimization method in this work. Retort pouch food is the mainstream type in the canning market owning to its various advantages, such as high heat transfer efficiency, light quality, low cost, and so on. However, the excessive sterilization problem is inevitable for the retort pouch food, because its sterilization technique is as same as the conventional canned food. The tofu cake, a traditional Chinese food, was selected as the object of sterilization in this study. The taste and color of tofu cake usually suffered from the problems of over-soft and excessive-dim after sterilization. Therefore, the gradient heating-up method was employed to optimize the sterilization process for the tofu cake. The specific research steps were as follows: (1) a mathematical model of tofu cake was established based on the unsteady solid heat transfer model, which included the determination of the heat transfer equation, the acquisition of thermo physical parameters, the convective temperature function of retort at each stage, and the calculation of convective heat transfer coefficient; (2) the finite element analysis was carried out using computation fluid dynamic (CFD) software. In this way, the temperature history of all nodes during the sterilization process of tofu cake was obtained on the basis of the establishment of geometric model, mesh generation, boundary loading, and various treatments; (3) the calculation of kinetics parameters and the screening of gradient heating-up modes. The sterilization value, a kinetic parameter which represented the bactericidal effect, was used as the constraint condition. The objective function included the surface cooking values and volume average cooking values at the same time. These functions were regarded as the limit of damage extent of food quality. Subsequently, a series of gradient heating-up modes were set up and numerically simulated. After that, the appropriate gradient heating-up modes were selected to meet the restrictive conditions. The cooking values were significantly decreased compared with the original sterilization method (CRT, 30 min/116℃); (4) the actual sterilization data were collected according to the optimum mode obtained in the third step. The analyzed and compared kinetic parameters were as same as the last one step, and the combined pressure limit of retort in the actual production was measured by the same method. Thus, an optimum gradient heating program was achieved. The gradient heating-up method were successfully used to optimize the retort process for the tofu cake in the current study. And the optimum conditions were as follows: first, temperature was heated up to 100℃and then maintained for 20 min; second, temperature was up to 120℃ and then maintained 15min. The results showed that this method could be used to ensure that the sterilization value was higher than 3 min, while the quality deterioration parameters surface cooking values and volume average cooking values were around 10.1% and 8.69%, which were significantly lower than the original sterilization process. Furthermore, the L-value, a-value, and b-value provided by the colorimeter and the actual photographs confirmed that the sterilization process could maintain the nature color of dried beans in a better way. Moreover, the taste of the quality maintenance was greatly improved because of the improved moisture content, shear, hardness, cohesion, and other related indicators. Besides, the gradient heating-up method could satisfy the long-term stable operation of sterilization kettles and met the safety limits of related industrial sterilization equipment.