Abstract: In this paper, a total least squares joint (TLS-J) adjustment method is proposed to the inversion of Mogi model with vertical and horizontal observational data. The proposed method considers the errors in both observation vector and coefficient matrix of the functional model of joint adjustment problem. Three forms of the minimum discriminate function methods are adopted to determine the weight scaling factor which are used to weigh the vertical and horizontal observation data. In view of the existing ill-posed problems in the joint adjustment, the L-curve method is adopted to determine the ridge parameter. Through practical examples, the total least squares joint method is systematically applied to the inversion of the Mogi model of Changbaishan Tianchi volcano. The results show that the discriminant function as the minimum can obtain the reasonable value of pressure source parameters and the relative weight ratio, which has a certain referential value to practical applications.