Oxidation pitches were prepared from AR mesophase pitch preoxidized for different time at 300 ℃. Carbon foams were produced with AR mesophase pitch and the oxidation pitches. Element content and thermal decomposition processes of the pitches were analyzed with Nitrogen/oxygen and Carbon/sulfur analyzer and thermal analysis instrument. The microstructure of carbon foams was observed with SEM. The effects of preoxidization at 300℃ on composition and TG of AR mesophase pitch were investigated. After preoxidizing for 2 h, 4 h and 6 h at 300 ℃, the content of oxygen increased from 0.85% to 6.60%, 10.47% and 11.31%. Carbon foams had lesser aperture when the oxidation pitches were used as the precursor. The compressive strengths of carbonized and graphitized carbon foams were 12.07 MPa and 9.06 MPa when preoxidizing for 6 h at 300 ℃.