The quality and physicochemical indexes of rice sour soup, made of glutinous rice, japonica rice and flour, were detected and the relative correlation with sensory scores were analyzed. Thereafter, the rice slurry was used to optimize the liquefaction and saccharification processes, as the reducing sugar and soluble solid content (TSS) were taken as evaluation indexes. The results showed that the highest sensory score was obtained as the raw material ratio was glutinous rice∶japonica∶flour 2∶1∶1. The sensory score was positively correlated with viscosity, total acid, reducing sugar, particle size, protein, TSS, b* (r=0.892, 0.862, 0.861, 0.861, 0.841, 0.822, respectively), while negatively with L* (r=-0.885). Moreover, a very complex relationship between the quality index of rice sour soup with different ratio of raw materials was found. The optimum conditions of rice slurry liquefaction were as follows: with the addition of liquefaction enzyme of 40 U/g, liquefied at 85 ℃ for 30 min, at pH 6. The optimum conditions for the saccharification of rice slurry were saccharified at 60 ℃ for 1.5 h, with the addition of 1 000 U/g saccharification enzyme at pH 5.