Abstract：Three silane coupling agents, 3-(aminopropyl)triethoxysilane (APTES), 3-(mercaptopropyl)- triethoxysilane (MPTES) and 3-glycidoxypropytriethoxysilane (GPTES) were used to modify the white carbon black derived from fly ash. The effects of amino, thiol and epoxy silane coupling agents on the dispersion of modified white carbon black were studied by FTIR, TGA, zeta potentiometer and SEM. The results showed that three different silane coupling agents were grafted successfully onto the surface of white carbon black. The dispersity of modified white carbon black was improved obviously, which was related not only to the particle size of modified white carbon black but also to the loading amounts of silane coupling agents. Among them, the modification effect of MPTES was the best. Under the conditions of pH=10 and n(MPTES):n(SiO2)=1.0:1.0, the obtained product had the best dispersity in alcohol, the size was 557 nm and the absolute value of zeta potential was 36.43 mV.