Abstract: In order to realize the harmless and resource utilization of desulphurization wastewater and fly ash. In this study, the desulfurization wastewater was solidified / stabilized by fly ash and cement and the best mass mix ratio of solidified body was obtained through equilateral triangle value test method The effect of different desulfurization wastewater on the compressive strength of solidified body was studied. The results show that the best mass mix ratio of solidified body is cement : fly ash : desulphurization wastewater : river sand = 1.03∶0.2∶0.5∶1.Under the best mass mix ratio, the compressive strength of solidified bodies prepared from different water samples after curing for 28 days is in the order of Inner Mongolia desulfurization wastewater>Shandong desulfurization wastewater>deionized water. The test results of X-ray diffraction (XRD) and scanning electron microscope (SEM) of three kinds of desulfurization wastewater show that the chloride ion in desulfurization wastewater reacts with 3CaO·Al2C in cement to form Friedel’s salt, which can effectively improve the compactness of the solidified body, and then improve the compressive strength of the solidified body. And the cross structure of ettringite and C-S-H gel in the solidified body made of desulphurization wastewater enhances the strength of the solidified body. The above two points also fully explain the differences in compressive strength of solidified bodies made from different water samples. In addition, the compressive strength test results show that the compressive strength of the solidified body made of deionized water, desulphurization wastewater from a power plant in Shandong and desulphurization wastewater from a power plant in Inner Mongolia after 28 days of maintenance meets the requirement of “concrete kerb” (JC/T899—2016), indicating that the solidified body made of desulfurization wastewater can be used to make kerb.