In order to alleviate the pressure of the mine drainage system and solve the problem of the construction impact and the increase of drainage cost caused by the water leakage phenomenon in the process of conveying the filling slurry to the goaf, the effect of absorbent resin on the performance of the obturator is systematically tested and analyzed by adding it to the obturator. The results show that the absorbent resin can effectively reduce the moisture content in the obturator, and the appropriate amount can improve the strength of the obturator, while the excess will lead to the decrease of strength. The microstructure analysis further reveals the influence mechanism of water-absorbing resin on the hydration reaction and pore structure of cement. The results can provide a theoretical basis and technical reference for the rational application of absorbent resin in mine filling engineering.