The sealing anchor mortar is a special cement-based engineered material with water-cement ratio (W/C) less than 0.18 and early (1 day) compressive strength greater than 40 MPa. It used high frequency shock pressure molding prepared mortar material with W/C of 0.09-0.18 and pure cement as the gelling material. Among them, the early (1 day) compressive strength of the mortar with W/C of 0.13 and 0.18 being more than 65MPa, and a high late (56 days) strength of 102.4MPa. SEM analysis showed when the W/C was 0.09, only the surface of the cement particles with early hydration (3 days) was hydrated, appearing a loose form and failed to stick together as a whole. The material with W/C of 0.13 and 0.18 produced more C-S-H gel phase and the overall cement particles cemented together whose microstructure was compact and uniform. Unhydrated cement particles mainly played the role of filling and micro-aggregates in the material.