The invention relates to a blade folding device, in particular to a guided missile tail blade folding machine. The guided missile tail blade folding machine comprises an upper support, a lower support, a blade screwing device, a first guide rail, a first sliding block, a holding device, a compression device and an air cylinder; the upper support is arranged on the lower support, and the lower support is provided with the blade screwing device used for screwing missile tail blades; the upper support is provided with the compression device used for downwards pressing a missile body and the holding device used for holding the blades, and the holding device is located between the blade screwing device and the compression device; and the first guide rail is installed on the upper support in the vertical direction, the holding device is in sliding connection with the first guide rail through the first sliding block, the air cylinder is arranged at the top of the upper support, and the output end of the air cylinder is connected with the holding device. The guided missile tail blade folding machine is reasonable and compact in structure and reliable in performance, the blade screwing efficiency is improved, the manual labor strength is reduced, and obvious deformation and appearance damage of the blades in the screwing process are avoided.