The invention relates to a process for treating excess 
sludge by utilizing 
fly ash. The method specifically comprises the following steps of: 1, feeding excess 
sludge to be treated which has the 
water content of between 80 and 90 percent, and 
fly ash in an amount which is 20 to 50 percent based on the 
mass of the excess 
sludge into a mixing 
agitator; fully mixing and reacting for 5 to 15min; feeding into a plate and frame dehydrator for 
dehydration to obtain sludge of which the 
water content is reduced to be between 35 and 45 percent; crushing the sludge into coarse particles with the particle size of between 3 and 5mm by using a sludge 
granulation device; feeding the sludge particles into a 
solar drying room, and 
drying for 24 to 48h at the temperature of above 40 DEG C and under the 
humidity of below 15 percent to ensure that the 
water content of the sludge is reduced to between 8 and 15 percent; and treating by sludge pulverization equipment and a high-speed 
airflow collision technology, wherein the particle size of sludge 
powder is 150 to 300 meshes and the water content is 5 to 10 percent after the treatment. The method has the advantages that: 
interstitial water, adsorbed water and capillary 
bound water in the excess sludge are absorbed into the 
fly ash; due to the characteristic of high 
permeability coefficient of the fly ash, the water in the fly ash is easily discharged; and the secondary 
pollution to the environment is avoided by appropriately treating the excess sludge.