Abstract: Expanded graphite-activated carbon composites(EG-ACs) were prepared by using one-step impegnation and chemical activation technology adopting sucrose as carbon source and H3PO4 as active agent.The composites were characterized by means of SEM and specific surface area analyzer.The effects of mass ratio of H3PO4 to sucrose and activation temperature on pore structure were investigated.The results show that most active carbon deposited on the surface of worm-like expanded graphite or filled in the entangled spaces in the shape of eggshell,only a few was in the expanded graphite.With the increase in the mass ratio of H3PO4 to sucrose and activation temperature,specific surface area and pore volume of the composites increased first and then decreased,the micropore grew to mesoporous gradually.The maximal specific surface area and pore volume were 1 978 m2·g-1 and 0.931 7 cm3·g-1,respectively,with the mass ratio was 0.9 and activation temperature was 350 ℃.