Abstract: In order to study the quasi-static performance of fly ash cenosphere/aluminum (FAC/Al) syntactic foam, quasi-static compression performance tests were conducted on the FAC/Al specimens by using a universal testing machine. The effects of different average particle sizes on the deformation and failure modes and mechanical performance of the aluminum matrix composite foam material specimens were investigated, and the stress-strain curves of the material specimens with different particle sizes under quasi-static load were obtained. And based on the stress-strain curves, the effects of particle sizes on the energy absorption performance of the material were analyzed. And the test results show that the compressive yield strength and energy absorption capacity and the ideal absorption efficiency of the material decrease with the increase of the particle sizes. In addition, by using the least square method to fit based on the stress-strain curves, the constitutive equation of FAC/Al under quasi-static load was given and verified, and the results show that the equation has a good fitting.