The invention discloses a waste combustion kiln. The waste combustion kiln comprises a kiln body fixedly arranged on the ground. A crushing cavity is formed in the kiln body. A transmission cavity located in the kiln body is arranged below the crushing cavity. A motor is fixedly arranged in the lower end wall of the transmission cavity. A belt wheel A located in the transmission cavity is fixedlyarranged on the outer surface of an output shaft of the motor. A belt wheel B is arranged on the right side of the belt wheel A. The belt wheel B is in power connection with the belt wheel A through abelt. A rotary shaft is fixedly arranged in the belt wheel B and rotatably penetrates through the upper end wall of the transmission cavity to stretch into the crushing cavity. The waste combustion kiln is simple in structure and convenient to use; and automatic feeding and discharging are adopted by the waste combustion kiln, heat energy generated during waste combustion is used for power generation, and thus, the environmental friendliness of the waste combustion kiln is effectively improved.