In order to solve the preparation problem of super-retarding concrete at the construction site of bite pile and explore the mechanism of retarder, the super-retarding concrete was prepared by adding sugar and sodium gluconate with a mass ratio of 7∶3 as composite retarder, and two kinds of preparing process, namely the primary stirring process and secondary stirring process were compared. The mechanical properties, microstructure, adsorption amount and hydration properties of super-retarding concrete were tested and analyzed by compressive and flexural testing machine, environmental scanning electron microscope (ESEM), total organic carbon analyzer and isothermal calorimeter. The results show that the setting time of concrete increases with the increase of retarder content. When the content of retarder is 0.38% (mass fraction), the initial and final setting time of the first stirring group are 31 h and 46 h, respectively, and the initial and final setting time of the second stirring group are 34 h and 50 h, respectively. When the content of retarder is 0.50% (mass fraction), the initial and final setting time of the first stirring group are 61 h and 78 h, respectively, and the initial and final setting time of the second stirring group are 65 h and 84 h, respectively. Under the two dosages, the 56 d compressive strength of concrete is all above 40 MPa, which can meet the construction requirements of the two working conditions. The secondary stiring process is helpful to further prolong the setting time of concrete and improve the fluidity of concrete mixture, but slightly reduce the compressive strength of concrete. The order of adsorption capacity of different retarders on the surface of cement particles is: sodium gluconate>sugar-sodium gluconate>sugar>sugar-sodium gluconate after blending. Mixing retarder can reduce hydration heat and restrain hydration of cement, so as to prolong setting time of concrete.