Abstract: A quantitative analysis on the average transmission speed of hepatitis B by using reversible catalytic model was carried out in natural population in Xuxhou.The result indicated that the fitness of reversible catalytic model made by us was good,the general fitness accuracy between theoretic estimated value and actual observed value amounted to 96.55%,maximum accuracy 99.85%.The result of fitness test was χ2=1.960,P>0.05.It was showed that the reversible catalytic model had its unique advantage in the measurement of hepatitis B average transmission speed in natural population.The data also indicated that the hepatitis B surface antibody was 94 positives among 1000 persons,At the same time 52 perons transferred to negative in Xuzhou downtown,the maximum prevalence rate of hepati-tis B in Xuzhou was estimated up to 64.6%,the low prevalence rate was thought of the wild application of hepatitis B vaccine.