The invention relates to the field of automatic assembling devices, in particular to a U-shaped hanging ring machining machine. The U-shaped hanging ring machining machine comprises a worktable, a hanging ring feeding device, a first conveying device, a first jig device, a punching device, a second conveying device, a second jig device, a bolt assembling device, a nut assembling device and two bending devices; the hanging ring feeding device is arranged on the side of the worktable, the first conveying device, the first jig device, the second conveying device and the second jig device are arranged on the worktable in sequence from left to right, two mounting grooves are formed in the first jig device, the two bending devices are arranged in the corresponding mounting grooves, the punchingdevice is arranged on the side of the first jig device, a first fixing device is arranged on the side of the first jig device, the bolt assembling device and the nut assembling device are arranged onthe two sides of the second jig device, and a second fixing device is arranged on the side of the second jig device. The machining efficiency of a U-shaped hanging ring is improved.