The invention relates to a grinding incinerator with a lifting fire grate, comprising a furnace body, and a feeder unit installed at the top of the furnace body, wherein the feeder unit comprises a grinding cylinder connected with the feed inlet at the top of the furnace body through a discharging cylinder; the grinding cylinder is installed on a rack in a rotatable manner and driven by a motor; one end of the grinding cylinder is a large-diameter fed end while the other end thereof is a small-diameter discharge end; a grinding piece integrally wound is arranged on the inner wall of the large-diameter feed end while multiple discharge holes are arranged on the side wall of the small-diameter discharge end; the discharging cylinder is arranged at the periphery of the small-diameter discharge end; annular material guiding space is arranged between the inner wall of one end of the discharging cylinder and the outer wall of the small-diameter discharge end and the other end of the discharging cylinder is interconnected with the furnace body; the furnace body comprises a lower incineration cavity connected with the discharging cylinder, and an upper incineration cavity above the lower incineration cavity; the upper incineration cavity and the lower incineration cavity are interconnected; the fire grate is installed in the lower incineration cavity and a flaming pipe is arranged at the top of the upper incineration cavity.