On a basis of the washout model and concentrations of anthropogenic tritium in rainwater around the Wolsong site, the washout coefficients of tritium by rainwater were calculated, and the validity of washout deposition model are estimated. As the result of that, the washout coefficients in 10 sampling stations around Wolsong site were in the range of $2.9{ imes}10^{-5};-;16{ imes}10^{-5};s^{-1}$ with the mean value of $7.21{ imes}10^{-5};s^{-1}$. The validity of the washout deposition model was confirmed by comparing the observed data with the calculated ones.