Abstract: Aiming at the search of impervious technique in an engineering tunnel, in-situ grouting by boreholes was adopted for grouting experimental research. The researches indicate that most rock strata in this area leak severely. By assuming the technology of two-step grouting, pounding ratios in most rock strata with severe leakage achieved up to 80% and in some area to 100%. But some boreholes need further investigations on grouting measures for improving pounding ratios effectively.