The oil sand water agent was optimized, and the Inner Mongolia Tumuji oil sand was taken as the experimental object. The effects of reagent concentration, reagents sand ratio, mixing time, mixing temperature to the tailings residual oil rate were investigated. According to Tumuji oil sands, the results show that under the conditions of reagent concentration of 3.50%, agent sand ratio of 0.4∶1.0, mixing time of 25 min, mixing temperature of 90 ℃, the tailings residual oil rate can reach 0.71%. The improvement reduces the water agent consumption and the residual oil rate of the tailings.