Abstract: In order to effectively improve the transport performance of high concentration cementing slurry in coal mine, naphthalene series and polycarboxylic acid type water reducing agents were used in experimental tests.The rheological properties, such as the yield stress and shear stress, etc, were analyzed under the help of r heometer. Considering the factors such as slump, slump flow, bleeding rate, etc, the flow characteristics of slurry were explored, and the impacts of water reducing age nt to the transportation performance of coalmine cemented backill slurry were researched. It turned out that when 1. 5% of naphthalene and 0.4% of polycarboxylic aci d type water-reducer were added, shear yield stress of slurry was reduced from 634.4 Pa to 301.6 Pa and 314.7 Pa. Plastic viscosity increased from 7.9 Pa.s to 12.1 Pa .s and 8.5 Pa:s respectively. Filling materials' bleeding rate increased with the increasing of the dosage of water reducing agent, but the polycarboxylate-bleeding rate was smaller. No bleeding under 0.3%. Taking environmental protection into account, polycarboxylate-based will be a better choice.