The invention discloses a belt conveyor capable of automatically adjusting the height. The belt conveyor comprises a conveyor belt, wherein a friction pad is arranged on an outer surface of the conveyer belt; teeth are arranged on an inner wall of the conveyor belt; the conveyor belt is connected with gears through the teeth; the gears are arranged on outer walls of rotary rods; the rotary rods are connected with rotors of motors through couplers; the tail ends of the rotary rods are connected with a bearing; a shaft protection cover is arranged on an outer wall of the bearing; telescopic rodsare welded to the bottom part of the shaft protection cover; telescopic rod protection covers are arranged on outer walls of rod connecting parts of the telescopic rods; a hydraulic rod is arranged on the bottom part of the right end of the shaft protection cover, and is connected with a hydraulic cylinder; and the hydraulic cylinder is arranged on the base. According to the belt conveyor capableof automatically adjusting the height provided by the invention, through arranging the hydraulic rod, the hydraulic cylinder and the telescopic rods, the conveyor belt can freely control a conveyingangle under the drive of the hydraulic rod and the hydraulic cylinder and through the assistance of a telescopic action of the telescopic rods, so that the requirement on conveying materials in various angles is met.