Abstract: In order to solve the problem of the traditional granular grouting material can’t be injected into deep bedrock with microfissure, grouting with sodium silicate chemical material was adopted for pre-grouting at surface ground. The silicate chemical material was suitable for pre-grouting at surface ground with a low viscosity, good injection, adjustable gel time, high strength of the consolidate body. the gel time which determines the success or failure of the grouting should be studied according to its flowing law . After reasonable formulation selection and scientific construction, success of sodium silicate on pre-grouting at the ground was completed. The result of pressure water test showed a good effect of sodium silicate chemical grouting.