The invention relates to a garbage preheating and drying device which comprises a garbage drying bed and drying drop devices. The garbage drying bed is formed by combining a plurality of groups of fire grate segments; and the drying drop devices are arranged at the tail ends of the last group of fire grate segments, soaked in the dense phase region of a circulating fluid bed, built by fireproof durable material, in a slope quadrangular frustum pyramid shape with unparallel table-surfaces and incline to the dense phase region along the garbage preheating and drying device. The width of the front end of each drying drop device can be smaller than or equal to that of the rear end of the drying drop device and can be also larger than or equal to that of the rear end of the drying drop device;the height between the front end and the rear end of the drying drop device is two to four times larger than the width of the longest end of the front end and the rear end; the number of the drying drop devices arranged in parallel along the width direction of the drying device can be more than two; and the distance between the rear ends of the adjacent drying drop devices is one-half to one timeof the width of the longest end of the front ends and the rear ends. The invention can effectively dry garbage with high moisture and prevent deflagration caused by unstable flow rate of the garbage entering the dense phase region of a destructor and enables the dried garbage to smoothly drop in the destructor.