The invention relates to a comprehensive mechanization coal-mining method of a heavy pitch course long well. The core of the invention adopts a plough conveying fully mechanised unit. The plough conveying fully mechanised unit is composed of a plough conveying machine and a covering type hydraulic support, wherein the plough conveying machine comprises a driving sprocket, a dragging plow chain, a plough, a motor, a frequency conversion control system, a gear box and a machine beam composed of a plurality of long beams; the hydraulic support comprises two double-stretching stand columns, a thrust gear, a four-bar mechanism, a top beam, a base, a covering beam, a side backplate and the like; each hydraulic support hoisting jack and each section of long beam of the plough conveying machine are connected by a crosshead to form a cubical space frame structure; a bottom adjusting beam, the side backplate, a cable-stayed jack and the like are combined to effectively prevent the whole set of equipment from turning over and sliding down. The operation state of the whole set of plough conveying unit is controlled by electrical liquid during operation to cause the working surface production to realize high-degree automation. The invention causes heavy pitch thin and middle-thickness coal bed course long well working surface to realize comprehensive mechanization mining, improves working surface production efficiency, lowers worker labor intensity and greatly ensures the production safety of the working surface.