Abstract: Based on the finite element software FEAP (Finite Element Analysis Program) developed at the University of California, Berkeley, refined micro finite element models are built for RC frames infilled with masonry walls combining the smeared crack element and the discrete crack element. The experimental results of a RC frame model tested at the University of California, San Diego are used to validate the rationality of the finite element models. Using the validated FEAP program, a multi-story frame is analyzed with the pushover analysis method. The trends of crack development, stiffness change and stress development are researched, and the interaction mechanism between infilled masonry walls and RC frames is studied. The failure mode and seismic performance of RC frames infilled with masonry walls are researched.