The invention discloses an efficient mechanical mining method for gently-inclined thin ore bodies. The method includes steps: step one, tunneling a drilling roadway of a first layer of a first section; step two, cutting waste rock of a foot wall; step three, forming side collapse vertical grooves; step four, constructing fan-patterned blast holes; step five, laterally blasting to form a footwall compensation space; step six, blasting in upper fan-patterned blast holes for stoping; step seven, constructing a connection roadway of a second layer of the first connection; step eight, tunneling the drilling roadway while cutting the waste rock according to procedures of the step one and the step two; step nine, repeating the step one to the step eight, and continuing stoping of a next section until stoping of four sections is finished. By the efficient mechanical mining method, defects of a breast stoping method and an upward horizontal cut-and-fill stoping method are overcome, and reduction of labor cost, relief of work intensity and the like can be realized by efficient mechanical operations. Furthermore, the efficient mechanical mining method is especially applicable to mining of gently-inclined thin ore bodies with high values or rare precious metals.