Abstract: Investigation of the effect of enzymatic hydrolysis of oyster (EHO) on learning and memory ability.The contents of major components and the molecular weight distribution of the EHO prepared respectively by adding neutrase, proteolytic enzymes and mixed enzymes were test, then the learning and memory ability were assessed using the Morris water maze (MWM) with one control group.The results showed that the EHO was rich in peptide, glycogen and taurine, and the molecular weights were from 1300～10000u.MWM test indicated that the proportion of spatial strategy of the treated groups were higher and the escape latency were significantly shorter compared to the control group.EHO3 group was the best one, the escape latency was (16.77±7.74) s (p<0.05) and the proportion of spatial strategy reached 85.71%.All the three EHO groups had more number of crossings, longer time in the center and longer distance in the target quadrant than that of control group in the spatial probe test.These findings suggested that certain amount of EHO could improve the learning and memory ability of mice.