In the manufacturing process of dog food, puffing process is one of the most central part, because the dog food composition of the raw materials are diverse, different forms, in order to save energy and production capacity to improve production, wet twin-screw puffing technology is increasingly used. Dog food pre-matured effect and the effect of expansion at the same time by the impact of the fineness of crushed raw materials, generally speaking, the most scientific fineness of crushed raw materials for dog food using 1.2 ~ 2.0mm diameter gong bottom screen, mesh requirements in the 16 mesh 1.18mm aperture, the sieve is less than 9% of the best, however, in order to respond to the market demand for consumer hobbies, the screen aperture of the finest control in 0.8 ~ 1.2mm However, at present, in order to meet the market demand of consumers, the finest aperture of the sieve is 0.8~1.2mm, between 18 mesh and 20 mesh. Dog food is subject to the special requirements of shelf life, extrusion puffing out of the pellet moisture is generally around 18% ~ 25%, so must be extruded puffing after the drying and dehydration process, in order to ensure the quality of dog food.