The invention relates to an orientation adjusting device for mine drilling and an adjusting method thereof. The orientation adjusting device comprises a main body assembly, wherein the main body assembly comprises a fixing column, a connecting block, a base, a plate body, a fixing block, a sliding rod, a lifting assembly, a drilling assembly and a switch assembly. A third motor drives a first connecting shaft to rotate, the first connecting shaft drives a first gear to rotate, the first gear drives a second gear to rotate in a bearing through a second connecting shaft, the second gear drives asupporting plate to rotate through a first rod body, the plate body is driven to rotate through a second rod body, the drilling assembly and the lifting assembly are driven to rotate through the fixing column and the connecting block, and a drilling position is adjusted and positioned. When drilling is needed, the connecting block is driven to move downwards under the action of a screw rod, a drill rod drives a drill bit to be close to the drilling position, the drill bit is flexibly adjusted effectively for drilling according to surrounding points needing drilling, the horizontal and vertical positions of a drilling machine do not need to be manually adjusted, and the use intensity of workers is reduced.