The rheological properties and fluidity of alkali-activated fly ash-slag grouting materials were studied by Brookfield R/S plus rheometer and Marsh cone． The effects of sodium silicate modulus and concentration and slag content on slurry were discussed． The correlation between rheological properties and Marsh fluidity was explored by grey relational analysis method． The research shows that the Marsh cone with an 10 mm inner diameter is suitable for the fluidity test of the alkali-activated fly ash-slag grouting material． The alkali-activated fly ash-slag grouting material is shear thicking slurry withing reological property index greater than 1． When the sodium silicate modulus is 1. 7，the sodium silicate concentration is 18%，and the slag content is 10%，it has good working performance． The correlation between Marsh fluidity of the slurry and the yield stress and plastic viscosity of the slurry is greater than 0. 8，and the correlation is good． The rheological property at the 20 s^-1 shear rate is the best correlated with the Marsh fluidity． The Marsh cone method can be used to detect the fluidity of the slurry．