Objective:To study the maximum volume of oral cavity (MVOC) of the young adults with normal occlusion and to explore the correlation of MOVC with the height,weight,mouth opening degree and masticatory efficiency.Methods:100 volunteers with normal occlusion(50 for each sex) were enrolled.MVOC was measured by the maximum water capacity method,the height,weight,degree of mouth opening and masticatory efficiency value of the subjects were measured.Results:The average values of MVOC of the male and female were (117.63±15.31) ml and (92.08±14.06) ml respectively(P<0.01).MVOC was positively correlation with the height(r=0.67,P<0.01),weight(r=0.63,P<0.01),degree of mouth opening(r=0.47,P<0.01) and masticatory efficiency(r=0.45,P<0.01).Conclusion:MVOC is moderate-positively correlated and low-positively correlated with mouth opening degree and masticatory efficiency.