Abstract: in order to study th ciffision mechanism of the chemical grouting for the coal mining face in the underground mine.a new ransparent sol model and nondestructive opical observation technodlogy were appied. A chemical grouting sinmulaton device was designed and the laser and CCD camera were appied to completethe visulization of the penetration grouting process of the ransparent sil model.Tthe image resuits showed that under the role of the gravitythe chemical grout woudbe difused in a pear shape,the verica difision distance would be longer t han thelatera dfifusion distance and would be different to the conventional al hape dfuson theory. Based on a mine shaft in construction of Hetaoyu Mline as a case,according tothe testresuts of the nocdel agrouting borehole design method vas providedwith the chenical grouting to conrol the secondary water infow of the working face in the mine shaft and the space distance between the group boreholes was reduced.After the engineering construction completed,the total water iflow of the mine shat wirking face were reduce from over 30 m -3/ h before the constution to 3 m3/ h and the water sealing rate was 90%. The requirements of the water prevention and eakage sealing were reached and could ensure the mine shaft sarety