Abstract: The open-celled aluminum foams were prepared by counter-gravity infiltration casting system. The quasi-static compression performance and the relationship between void content and the main preparation process parameters were investigated. The experimental results show that there is hardly macro-defect in the foam samples prepared by counter-gravity infiltration casting. The foam materials exhibit uniform pores distribution and structural integrity of every pore. The void content affects the mechanical properties of aluminum foams strongly. The yield stress and plateau stress significantly increase with the decrease of void content. Raising pre-heating temperature, increasing packing pressure and extending dwell time are effective to lower the void content in aluminum foams.