The water absorption of ceramsite decreased monotonously at the firing temperature of >1050. Water absorption determination reference GB/T3810.3 - 1999. As can be seen from Figure 1, the sintering temperature has a great influence on the water absorption of ceramsite. The firing temperature is lower than 1050 DEG C, the water absorption rate of change is complex, formed by the fly ash hydraulic generating pore structure and roasting initial water and organic burning and mineral decomposition of the pores, and is affected by the negative factors of the low melting point material penetration. The firing temperature is higher than 1050 DEG C, the molten liquid densification effect, melting quartz glass material with low viscosity, easy to penetrate into all kinds of crystal particles in the gap, the particle structure of adsorption material is too dense, so that the pores are less. With the increase of sintering temperature, the dense structure of the particles increases, and the porosity of the fly ash aggregate decreases, which results in a rapid decrease in the water absorption of the ceramsite.