Abstract: Macro mechanical behavior of Al particles reinforced polytetrafluoroethylene(Al/PTFE) was studied by finite element method. According to statistics on Al particles and microvoids by SEM, representative volume element (RVE) models considering particles and microvoids distribution as well as geometry were reproduced. By using ABAQUS finite element software, mechanical behavior under uniaxial compression of both two dimension and three dimension models were simulated. Also periodic boundary condition (PBC) was applied to improve accuracy of calculation. Quasistatic stress-strain curves of composites of various particle fractions were analyzed, and especially results from simulations and experiments were compared. The results indicate that both two dimension and three dimension models are effective methods to predict the mechanical behavior of Al/PTFE, and two dimension models are more efficient. Furthermore, the validity and effectiveness of the PBC are verified.