In order to explore the effects of different oral processing methods on starch digestion characteristics in vitro, highland barley steamed bread and wheat steamed bread were used as experimental materials. The effects of five in vitro simulated oral processing methods (cutting, cutting with vortex, cutting with grinding, cutting with vortex and mixed with artificial saliva, and cutting with grinding and mixed with artificial saliva) on starch digestion characteristics were studied, and compared with oral processing in vivo to optimize the in vitro simulated starch digestion method of steamed bread products. The results showed that the particle size of food pellets after in vitro simulated oral processing (155-350μ m) and water content (62%-64%) were higher than those of oral chewing in vivo (110-300μm,57%-59%). However, the hardness of the food pellet by simulated oral processing in vitro (0.73-3.77N) was lower than that of oral chewing in vivo (2.44-4.39N). Compared with the group without artificial saliva, the simulated oral processed food pellet obtained after adding artificial saliva was closer to oral chewing in vivo in terms of physical and digestive properties. Among all in vitro methods, the method of cutting with vortex and mixed with artificial saliva could best simulate chewing in vivo, and could be used as a pretreatment method for steamed bread products to simulate starch digestion in vitro. The mode and level of mechanical damage and the mixing mode of solid particles and saliva would affect the formation of food pellets, and then affect the digestion kinetics of steamed bread. The results of correlation analysis showed that there was a significant negative correlation between the final hydrolysis rate and particle size of steamed bread in the later stage of digestion (r=-0.93494, P<0.05). Considering various indicators, in vitro simulated oral processing method of cutting with vortex and mixed with artificial saliva was most suitable for in vitro simulated starch digestion of steamed bread products.