The invention belongs to the technical field of agricultural machinery and relates to an adjustable U-shaped bolt combined structure. The adjustable U-shaped bolt combined structure is characterized in that each cross threaded rod is provided with threads; one end of each cross threaded rod is of a ring structure; every two cross threaded rods are arranged on a vertical threaded rod in a sleeved mode through the ring structures; two fixing nuts are arranged on the outer sides of the two ring structures respectively, so that U-shaped threaded rod structures are formed; a rack is clamped between the two cross threaded rods on each vertical threaded rod, and a handle of an operating component is clamped between the two U-shaped threaded rod structures; four metal plates are arranged on the cross threaded rods to form a # shape, so that the handle of the operating component is clamped and then fixed through the nuts. The adjustable U-shaped bolt combined structure can solve the problems that the size of a traditional U-shaped bolt can not be adjusted, and the handles of the operating components with different sizes can not be arranged on the rack, and is simple in structure, convenient to use and easy to popularize.