The invention discloses a hydraulic machine of a tubular structure. A pipe serves as a connecting rack. A main oil cylinder is arranged at one end of the pipe. A puncher pin or an extrusion head are arranged at the front end of a piston rod of the main oil cylinder. A forming die is arranged at the other end of the pipe or in the middle of the pipe. A feeding cavity is formed in the front portionof the forming die and located between the main oil cylinder and the forming die. The center axes of the main oil cylinder and the die are located on the same horizontal or straight line. According tothe hydraulic machine of the tubular structure, the pipe is adopted for replacing a multi-guide column structure in the prior art, oil cylinders or the die is directly fixed to the ends of the pipe or the middle of the pipe, a threaded or clamping key or flange connecting mode also replaces an upper-lower beam structure in the prior art, the hydraulic machine of the tubular structure is formed, accordingly, a large number of parts (especially large-diameter guide columns and two end oil cylinder link beams with the quite high cost) are saved, the size of overall equipment of the hydraulic machine is remarkably reduced, the structure is more compact, transportation, mounting and maintenance are more convenient, and the economic benefit is remarkable.