The invention relates to the technical field of machining, in particular to a universal self-aligning bearing. The bearing comprises a base, a screw rod and a top head; the top head is connected with the base through the screw rod, a positioning groove is formed in the end, connected with the top head, of the screw rod, a hemispherical groove is formed in the bottom of the positioning groove, and a T-shaped groove is formed in the upper portion of the hemispherical groove in the positioning groove; the top head comprises a hemispherical part and a supporting part, the plane end of the hemispherical part is connected with the supporting part, the hemispherical part of the top head stretches into the positioning groove, and is in contact with the hemispherical groove in the positioning groove, and the top head is screwed into the positioning groove of the screw rod in a threaded connection manner; the radius of the hemispherical part is larger than that of an outlet of the T-shaped groove; and the bearing is novel in design, reasonable in structure, and flexible, simple and easy to operate. The top head and the screw rod are in spherical face contact, three freedom degrees of the top head can be limited, and the top head can rotate around the axial directions of X, Y and Z.