Abstract: Oat beverages were prepared after the oats were heat treated by frying,normal steaming and high-pressure steaming respectively. The influences of heat treatments methods on the microstructure of oat surface were investigated,as well as the qualities of the corresponding oat beverages including soluble solid content,protein content,distribution of peptides molecular weight,particle- size,color,flovour compounds and sensory quality.Compared with frying and normal pressure steaming,high- pressure steaming had the greatest influence on the microstructure of oat and significantly reduced the average particle- size in the corresponding oat beverages( p < 0.05),and the ratio of peptides with high molecular weight was the smallest. Meanwhile,high- pressure steaming significantly increased the soluble solid content and protein content in the corresponding oat beverages( p < 0.05).Compared with normal pressure steaming,frying could significantly increased the soluble solid content and protein content in the corresponding oat beverages( p < 0.05),and the ratio of peptides with high molecular weight was much bigger. Oat beverages prepared by frying and high- pressure steaming had more flavour compounds.The oat beverages prepared by frying were dark yellow,while the ones prepared by the two kinds of steaming were obviously milky white and had better sensory quality than the former( p < 0.05).