With the aim to overcome the difficulty of grouting into aquiferous stratum in which karst fissure is weeny,both the home and field experiment of acid dissolving to expand karst fissure were carried out.The experiments indicated that the reaction between hydrochloric acid and limestone was active and changed rapidly in the initial 10 minutes and the reaction became steady at 40 minute after the inpouring of hydrochloric acid into limestone;when the concentration of hydrochloric acid was 20% around the effect of reaction was the best;after the inpouring of hydrochloric acid into limestone by borehole the water discharge of borehole increased markedly,and the relative increment of water discharge of borehole was between 26.4% and 133.3%.It offers theoretic foundation to increase the grouting amount of aquiferous stratum.