Abstract：Through the comparative research on applicability and superiority of Total Least Squares(TLS) and least squares in the space rectangular coordinates tranformation with 3-D small angles, it is found that in this kind of 3-D coordinate transformation because there are observational errors of the point coordinate in both the previous and new coordinate systems,if the coefficient matrix A and observed vector b of the error equation are corrected simulaneously with the TLS,thus more reasonable computation model can built out.The calculated example has proved that the more accurate coordinate transformation parameter solution can be given with TLS as compared with the LS.
