Abstract: The high concentration of hydrolyzed polyacrylamide(HPAM) in the produced water of polymer flooding in high calcium magnesium reservoir leads to the deterioration of the water quality of the conventional oil separation coagulation filtration/air flotation process and the blockage and fouling of filter materials. Therefore, it is urgent to develop the treatment technology. Ceramic membrane has attracted more and more attention in oil and gas field wastewater treatment because of its good effluent quality, anti-fouling performance, acid and alkali resistance and other advantages. Based on the problem of high HPAM concentration in the produced water of polymer flooding in high calcium magnesium reservoir, in order to improve the effluent quality and stable operation, this paper carried out the study on the effect of chemical flocculation+ceramic membrane and ozone oxidation+chemical flocculation+ceramic membrane pretreatment on the effluent quality and fouling of ceramic membrane. In this study, the feasibility of the combination of two pretreatments(coagulation, and ozone oxidation combined with coagulation) with ceramic was studied. Experimental results demonstrated that both the pretreatments could effectively alleviate the membrane fouling and enhance water quality of the ceramic membrane. The water quality of treated water by ozone oxidation, coagulation and ceramic membrane met the injection requirements(SYT 5329-2012)as follows:turbidity <0.2 NTU, oil content<10 mg/L, COD<2000 mg/L, mean particle size<0.8 μm. Membrane fouling caused by surface entrapment was proved to be obviously alleviated when artificial wastewater was pretreated by ozonation and chemical flocculation. This study provided technical support for the treatment of polymer flooding produced water and HPAM produced water in high calcium and magnesium reservoir.