Abstract: To consider the correlations among different failure modes of ancient timber architecture, based on Copula function, a new seismic vulnerability analysis method was proposed by taking a Chinese ancient architecture of Ming Dynasty as the study case. First, according to the structural characteristics and historical earthquake damage data of ancient timber architecture, inter-story displacement angle and rotation angle of mortise and tenon joints were chosen as seismic demand parameters and the incremental dynamic analysis method was used to build the vulnerability curves of the structure for different failure modes. Second, based on the incremental dynamic analysis results, two-dimensional frequency histogram was drawn to select the appropriate Copula function. Based on Copula function, the vulnerability curves that consider the correlation of different failure modes were established. Finally, the first-order bound method was used to build vulnerability curves of the structure. Results show that the vulnerability of timber architecture based on Gaussian Copula function is the greatest. The seismic vulnerability of the ancient timber architecture ranges in the upper and lower boundary of the first-order bound method.