The invention provides a sill pillar-less sublevel caving method for an inclined medium-thickness ore body. The sill pillar-less sublevel caving method for an inclined medium-thickness ore body comprises the fpllowing steps of carrying out sublevel stoping, finishing rock drilling in an access passage arranged in a vein formation direction, carrying out explosion and carrying out ore removal. The sill pillar-less sublevel caving method for an inclined medium-thickness ore body is characterized in that on each one stoping blast-hole surface, two stoping blast holes located at a side of a footwall of a stope section are communicated with a previous stope section so that a diversion mouth is formed; and other stoping blast holes are communicated with the previous stope section and form a triangular jamb on the top of a side of a hanging wall of the stope section. The sill pillar-less sublevel caving method for an inclined medium-thickness ore body has the advantages that through control of depth of the different stoping blast holes, the triangular jamb is formed on the top of the side of the hanging wall of the stope section so that it is avoided that waste rocks produced in the previous stope section untimely enter into the stope section; and a granule gravity flow of the previous stope section is introduced to the side of the stope section in a primary ore drawing stage and thus the diversion mouth is formed so that broken ore moving and removal conditions are improved and the problem of a large ore loss dilution rate is solved.