According to Peierls phase transition theory on the basis of the electron-phonon interaction, the Peierls phase transition temperature of a one-dimensional organic conductor TTF-TCNQ is computed by using the deformation potential model with the data calculated by using a semi-empirical crystal orbital method. The result indicates that the Peierls phase transition temperature of TTF chains is lower than that of TCNQ chains, which demonstrate that the electron-phonon coupling interaction in TTF chains is weaker than that in TCNQ chains, and the metal-insulator phase transition in TTF-TCNQ at 54K mainly takes place in TCNQ chains.