Based on the Yangtze River tunnel project constructed by a slurry shield in Nanjing, the discharged sand soil in the field was adopted as the material of the back fill grouting in the laboratory. The grout mortar tests have been carried out and the synchronous grouting parameters, including compression strength and shear strength, initial setting time, fluidity, consistency, bleeding rate, and permeability of grout mortar have been measured by the laboratory experiment, and the mixture ratio of the back fill grouting was also discussed to improve the grout feature. The results indicate that:the excavated soil from slurry shield tunnel can be re used as the material of the back fill grouting in the sand stratum; proper selection of binder/sand ratio and fly ash/cement ratio improves the performance of the synchronous grout.