To improve the borehole sealing effect of coal seam water infusion, especially that of coal seam with low permeability and high rigidity, this study investigated the performance test optimization of two cement-based sealing materials. The borehole sealing effect of this coal seam requires high-pressure water infusion. Result shows that when the water-cement ratio is 0.4 and the amount of fiber expansive agent is 10%, the new borehole sealing material displays microexpansion. In addition, the 1-day compressive strength reaches 16 MPa. This result satisfies the material compressive strength requirement under 30 MPa high-pressure water infusion. The sealing performance is also excellent. According to the scanning electron microscopy analysis of new borehole and traditional borehole sealing materials, the surface of new borehole sealing material shows no holes and possesses compactness. The sealing effect is superior to that of other traditional sealing materials. This effect can satisfy the sealing requirement of coal seam water infusion. The new borehole sealing material is considerably significant for the improvement of the water infusion effect.