Abstract: Significant results have been achieved in the application of distributed underground water reservoirs inShendong areaNingdong area has begun to demonstrate its feasibilityHowever，the mine water in Ningdong area is mostly of high turbidity and high salinity，so the pretreatment of the reservoir water is requiredThe experiment compares the flocculation effect of fly ashbased composite flocculant and unfilled coal ash flocculant，and explores the influence factors of fly ashbased flocculant，and determines the optimal dosage and test conditionsIn view of the characteristics of high turbidity and high salinity mine water，this experiment，using fly ash as raw material，to obtain high turbidity and high ore by mixing it with polyacrylamide（PAM），polyaluminum chloride（PAC） and chitosan，gets flocculants for treating high turbidity and high salinity mine waterThe experiment compares the flocculation effect of fly ashbased composite flocculant and unfilled coal ash flocculant，and explores the influencing factors of fly ashbased flocculant，and determines the optimal dosage and test conditionsThe experimental results show that：1The treatment effect of mine water in the five treatment groups is：PAM+PAC+chitosan+fly ash >PAM+PAC+chitosan > PAM+PAC>PAM>PAC；2The optimum condition of fly ash composite flocculant in temperature is 25° C，pH 7，stirring strength 220 r / min，stirring time 20 min；3Under the optimal conditions，the removal rates of salinity，suspended solids，calcium ions，total hardness and sulfate by composite flocculants are 1216%，9804%，8057%，7786% and 9544%；4It is feasible to use fly ashbased composite flocculant as pretreatment flocculant for the treatment of high salinity high suspended solid water in the groundwater reservoirThis article provides experimental theoretical basis and technical support for the pretreatment of flocculation in the groundwater reservoir.