The invention discloses a self-straightening spherical universal joint. The self-straightening spherical universal joint comprises four parts: (1) a ball joint, (2) an axial length self-adjusting slide sleeve, (3) a self-straightening spring, and (4) an end fixing piece. When the self-straightening spherical universal joint is used, a rotating joint is connected in; one end of a steam outlet pipe is fixedly connected with one end of the universal joint; a universal joint axial groove-carried slide sleeve (length adjusting guide sleeve) is arranged at the other end of the universal joint, and is connected with a fixed frame arranged in a cylinder outlet; and a universal joint center connecting piece is provided with the self-straightening spring. During working, power from rotation of a cylinder is transferred to the universal joint axial groove-carried slide sleeve through the cylinder and the universal joint connecting piece, is transferred to a universal joint shaft, and is transferred to the other end of the universal joint to a rotating joint connecting piece to a rotating joint through joint pin shafts arranged on four spherical joints and forming multiple angles in space. The self-straightening spherical universal joint eliminates radial force generated by rotation of the cylinder to an inner pipe of the rotating joint, and reduces the damage times of the rotating joint.