<p>We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate. The mass ratio of graphite to Al(H₂PO₄)₃ changed from 0.5:1 to 4:1, and the impregnation time changed from 1 to 7 h. The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique. To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures, the samples were put into a muffle furnace for a cyclic heat test. Based on SEM, EDS, DSC techniques, analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite: Al(H₂PO₄)₃ as 1:3 for graphite impregnation treatment. Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.</p>