Through the analysis about the working principle of anti-off chain mechanism, the chain-bucket shearer’s mining adaptability is studied. Two aspects of the work were done. On the one hand, the computer aided design software CAXA was used to design sketch, on the other hand, the software SOLIDWORKS was employed to draw three-dimensional stereogram and simulation assembly, to improve the design on anti-off chain mechanism. The primal problem of chain detachment is solved, and the height, total quality and cost are reduced. The new machine can mine 1.0~0.5 m coal seam, even thinner one.