Abstract: To better understand the stability performance and bleeding property of cement-based grouting slurry, a new test device was improved to get the separated-water thickness value of slurry samples at every time, and these samples were made and sorted according to the certain proportion of the water-solid ratio(0.6:1 to 3:1), fly ash content(0-90%) and sodium silicate content(0-12%). The growth theory for separated-water thickness was introduced, and the growth curves for all formulations were plotted. The slurry stability measurement method was classified, and the equivalence relation between the direct measurement method of slurry stability and the indirect measurement method was verified. The results were as follows:As the water-solid ratio increases, the slurry stability decreases. Fly ash can prolong the final water-separating time of slurry and improve the stability of slurry while sodium silicate can shorten the water-separating time. All the growth curves show a "half-C" shape and the results of indirect measurement and direct measurement are not equivalent.