Abstract: In order to solve a high fine dust problem of a difficult wetting and high dust produced in fully-mechanized top coal caving mining face,based on No. 20107 f ully-mechanized top coal caving mining face in Wangjialing Mine as the engineering background,in combined with the previous water injection test and the site actual condi tions,a combined water injection test with"a long periodical static pressure + alternative dynamic and static p ressure + static pressure in stress influence zone' 'was conduct ed. With the comparison study on the seam wetting and dust control effect with different water injection methods and different space of the boreholes,the water injection tec hnical parameters suitable to the type seam were obtained. The site practices showed that with the combined water injection technology,the wetting radius could be increas ed to 3 m. In the water injection area with a borehole space of 5 m,the total dust control efficiency could be over 57% and the respirable dust control efficiency would be 7 0%. Thus the dust danger problem of the coal mining face could be efficiently solved and the effect was obvious.