Microstructure and Hydration Characteristics of Flyash Treated by Highenergy Ball Milling Xing Weihong\ \ Gao Qiongyin [WT5”BZ〗 In this paper, Highenergy ball milling method was used to treated the flyash.SEM and BET methods were used to study the microstructure and specific surface of various flyash treated for difference time by ball milling. Results showed that particles and specific surface of flyash decreased remarkablely with the increasement of ball willing time, the biggerhard glass pearls were borken and its surface became irregular .Thermal analysis showed that the hydration exothermic heat increased for the flyash treated by ballmillingcement system.The pressing strength of hardening body of flyash treated for 5 hours by ballmillingcement system increased 4 times than that of raw flyashcement system.:[WT5”BZ〗\ highenergy ball milling;\ flyash;\ microstructure hydration characteristic Xin Weibhong:[WT5”BZ〗\ Lect., Institute of Material Science, WUT, Wuhan 430070, China.