The work aims to study the effect of different pore sizes (the diameter of internal pores of aluminum foam) on the compression and energy absorption properties of open-cell aluminum foam with spherical pores in the process of quasi-static compression. Quasi-static compression experiments were carried out on three aluminum foam samples of dif-ferent pore sizes. The stress-strain curve of aluminum foam was obtained by quasi-static compression test, and the energy absorption-strain curve was calculated by the stress-strain curve. When the pore size of the aluminum foam increased from 5 mm to 9 mm, the yield strength of the open-cell aluminum foam with spherical pores increased by 4.6862 MPa, the maximum energy absorption efficiency was increased from 24.45% to 27.71%, and the mechanical properties and energy absorption properties were improved. The compression and energy absorption properties of aluminum foam are enhanced with the increase of the pore size of the open-cell aluminum foam with spherical pores.