Abstract: The technology of coating TiO₂ film on the surface of ultra fine calcined coal kaolin particle was studied.It is shown that temperature and time,amount of surface modification agent,pulp density and stirring velocity are the important factors of influencing the effect of coating.The coating product,which was acquired on the optimum conditions,was tested and analyzed by SEM and TEM.The results show that titanium dioxide thin film on the ultra fine calcined coal kaolin is well distrbuted and compact,the thickness of film is about 150nm.