Shaking table test of an intact historic timber structure was carried out， and its failure modes， acceleration time history curves and relative displacement time history curves were obtained. On the basis of validity of Finite Element Model （FEM） of the test model， the looseness FEMs were established. The influence of looseness mortise-tenon connection on the dynamic characteris tics and responses of ancient timber structures was analyzed by the dynamic response analysis of the looseness FEMs under earth quake action. The results show that the natural frequencies of the looseness FEMs are lower than that of the intact FEM， and the natural frequencies of the looseness FEMs decrease significantly with the increment of the damage degree of mortise-tenon connec tion. The acceleration responses of column base and column frame， displacement response of column base and base shears of loose ness FEMs are smaller than those of the intact FEM， and all of them decrease with a larger looseness of mortise-tenon connection. The displacement responses of column frame of the looseness FEMs are larger than that of the intact FEM， and the responses in crease with a larger looseness of mortise-tenon connection. In addition， the cumulative energy dissipation （CED） of the looseness FEMs increases continuously with the increase of peak ground acceleration. With a larger looseness of mortise-tenon connection， the CED of each structural layer of the looseness FEMs increases gradually， and then decreases when the looseness exceeds a cer tain value.