Abstract: Abstract: In the feed processing process, the main factors including the composition of the raw materials, the conditioning and pelleting, and the size of the crushed particles affected the feed quality. With the advent of no-resistance/anti-resistance era, probiotics and other heat-sensitive antibiotic substitutes are used in feed formulations. In the feed processing process, higher tempering temperatures cause the loss of heat-sensitive feed ingredients such as probiotics. The lower temperature causes the lower sterilization. The objectives of this study were to systematically determine the effects of conditioning temperature and length-diameter ratio of ring die on feed quality and heat-sensitivity ingredients retention rate. Bulk raw materials of this formulation were processed by the expander, and the starch gelatinization degree was 69.13%. The ripened mash feed was pelleted with different temperature conditioning, and the length-diameter ratio of ring die was 6:1, 8:1 and 10:1, and the conditioning temperature was 50, 55, 60 and 65℃, respectively. The results are as follows: When the length-diameter ratio of ring die was 6:1, the starch gelatinization degree of 65℃ group was significantly higher than 50, 55 and 60℃ group; the PDI (pellet durability index) of 65 ℃ group was significantly higher than 50℃ group; the percentage of shaped pellets of 50℃ group was significantly lower than the other groups; when the length-diameter ratio of ring die was 8:1, the hardness of 65℃ group was significantly higher than the other 3 groups, the PDI of 60℃ group was significantly higher than that of 50 and 55 ℃ groups, and the particle formation rate of 50℃ group was significantly lower than that of 65℃ group; when the length-diameter ratio of ring die was 10:1, power consumption per ton of 50℃ group was significantly higher than other treatment groups. The interaction between the conditioning temperature and the length-diameter ratio of ring die has a significant effect on the gelatinization degree of the starch; the conditioning temperature and the length-diameter ratio of ring die have a very significant effect on the particle hardness and the PDI; the length-diameter ratio of the die hole has a very significant effect on the retention rate of lactic acid bacteria; the conditioning temperature, the length-diameter ratio and their interaction have a very significant effect on the electricity consumption of tons of material. The results showed that: The feed quality is affected by the conditioning temperature and the ratio of die length to diameter. When raw materials are pelleted in low conditioning temperature, the length-diameter ratio of ring die plays higher effect than conditioning temperature, 55~60℃ is recommended, and length-diameter ratio of ring die of 6:1 is recommended. It is of great significance to save feed production cost and materials costs and to realize the accuracy of diet. With the advent of non-antibiotics, the application of heat-sensitive antibiotic substitutes or high-price heat-sensitive additives in diet, this process will surely play an essential role.