This article studies the construction of Bayesian confidence interval for the difference of two proportions in the matched-pair design, and applies it to the equiva-lence or non inferiority test. Under the Dirichlet prior distribution, the exact posterior distribution of difference of two proportions is derived. The tail confidence interval and the highest posterior density (HPD) interval are studied, and their frequentist performance are investigated by simulation in terms of the mean coverage probability of interval. Our results suggest to use tail interval at Jeffreys prior for testing equivalence or non inferiority in matched-pair design.