The purpose of this study is to improve the grouting method for fractured rock masses. So experimental study is executed in order to understand the properties of grouting injection and seepage flow in hydraulic fractured aperture. This paper grasps the effect of the properties of grouting stage due to the various conditions such as width of the aperture, viscosity of the grout, water cement ratio and injection flow rate using flat plate fractured model in a laboratory experiment. From the results, it is proposed to select the relationship between the most suitable grout mix (water cement ratio) and width of the aperture to be injected according to the properties of grouting stage.