In order to study the influence of carbon material conditioning on sludge electrical dewatering performance and combustibility of sludge cake, sludge was pre-conditioned by using activated carbon and graphite, and analyzed the characteristics of sludge and dissolved organic matter (DOM) at both electrodes. The results showed that the electro-dewatering rate at cathode was increased after treated with carbon materials, and the promoted effect of graphite was more than the other three carbon materials. The average dehydration rate of the cathode increased from 0.074g/L to 0.095g/L when graphite was added in a small dosage of 5%TSS. Carbon materials could enhanced the conductivity of sludge system and electrophoretic mobility of sludge floc, which result in the porosity of sludge cake at cathode was increased. The pore volume of cathode mud cake was 0.1147cm³/g when the dosage of carbon materials was 0%TSS,but the pore volume of cathode mud cake were was 0.119、0.122、0.146、0.157cm³/g when the amount of AC-0、AC-1、AC-5、graphite was 20% TSS. In addition, the DOM concentration and protein substances in filtrate of both electrodes were decreased after treated with carbon materials, it can relieve the block of filter cloth; the energy consumption per mass of water removed can be reduced after being treated with carbon materials, The energy consumption required to remove water per mass of water was 6.75kW·h/kg, when activated carbon was not added separately, and when the dosage of AC-0、AC-1、AC-5、graphite were 20% TSS, the energy consumption decreased to 5.64、5.22、5.20、5.11kW·h/kg, and the water content of mud cake decreased from 58% to 45%, the calorific value and sustainable combustion time of sludge cake treated with carbon materials were enhanced, when the amount of graphite was 20%TSS, the calorific value of sludge cake increased by 17%. which can beneficial to the subsequent utilization of incineration.