MSWI fly ash is well known a hazardous industrial waste in the world, the characteristics of ash in cement slurry treated by promising technology - thermal degradation with salting precipitation are studied in this work , it can be efficient to reduce dioxin and Pb-metal to the legal limit. So we can not only accomplish “zero waste policy” but complete the “resources circulation.” Four characteristic of cement slurry were adopted to study the feasible of MSWI fly ash as alternative of cement material in this work. According to the results obtained, the detoxic ash addition increases the cement slurry initial and final setting time. Because of the hydration reduced ,more substitution of innoxious ash makes more drying shrinkage. Then we choose two mixture ratio: water cement ratio - substitution rate are 0.35-5 % and 0.37-10 % to compare their porosity, the total pore volume decrease 34.7 % and 47.6 % , the pore diameter decrease 28.4 % and 30.7 %. The compressive strength of cement slurry which substitution rate below 10% are 26.6 to 43.1 MPa. In this study, deduce this work that the slurry of low water cement ratio (0.30 to 0.37) and low substitution rate (5 % and 10 %) have more extension of application. Compare with the pre-treatment ways of MSWI fly ash, thermal degradation have higher cost than the solidification process with cement, but the beneficial from utilization also can keep the cost down, so this is worth of discussing in the future.