The diatomite/cellulose filter aids were prepared using raw diatomite and cellulose via sol-gel technique. The effect of cellulose/diatomite, distilled water/cellulose, EtOH/diatomite, ammonia concentration and temperature on the properties of diatomite/cellulose filter aids were investigated. The filtration efficiency of diatomite, cellulose and diatomite/cellulose filter aids was compared. The influence of diatomite/cellulose filter aids on slightly polluted water filtration was studied. Results indicated that when 40 mL distilled water dissolved 1.0 g cellulose, 20 mLEtOH carried 1.5 g diatomite, the ratio of diatomite to cellulose was 0.67, the concentration of ammonia was 5×10^-4mol/L, the temperature was 60℃,the best diatomite/cellulose filter aids were achieved. The efficiency of diatomite/cellulose filter aids was obviously better than that by diatomite and cellulose filter aids. The pollutants removal efficiency could increase by using the diatomite/cellulose filter aids in the direct filtration process to treat the micro-polluted raw water. The results showed that the combination of filtration and micro-filtration membrane could achieve excellent permeate water, which met the Standards for Drinking Water Quality(GB5749-2006).