In order to expand the application scope of fly ash,reduce its pollution to the environment,and seek the formulation and preparation of a new water treatment filter,the unburned fly ash filter material was prepared after milling,molding,and self-cooling in laboratory,with fly ash and clay as main ingredient,lime,gypsum and cement as activating agent,H₂O₂ and NaHCO₃ as vesicant.The result shows that the optimal mass ratio of raw material for unburned fly ash filter material,with porosity as performance evaluation index,is 46.30% of fly ash,13.89% of clay,18.52% of lime,13.89% of cement,1.85% of gypsum,and 5.55% of pure H₂O₂.The porosity under this optimal mass ratio is 72.24%.