Abstract: Because there was no suggestion value of period shortening factor of concrete frames with buckling-restrained brace （BRB) in chinese code, the authors researched 48 different cases, with the consideration of infill wall's nonlinear performance to find the proper value of period shortening factor for different seismic design requirements. The conclusion is that the period shortening factor relates to the displacement requirement of seismic structure and the influence of structural system to the period reduction factor is not obvious. Finally, the authors gave the suggested values of period reduction factor for concrete frame with BRB.