Disclosed is an automatic compensation mechanism for a hinge seal gap in a spherical compressor. A cylindrical hinge formed around a central pin (1), a rotating disk pin seat (81), and a piston pin seat (16) of the spherical compressor. A fan-shaped insert (14) thicker at both sides and thinner in the center thereof is disposed at the bottom of a sump (161) on the pin seat of the cylindrical hinge. The shape of the insert (14) marches the shapes of the sump (161) and of the external cylindrical surface of a semi-cylinder (811) on the pin seat of the cylindrical hinge respectively, forming a dynamic seal fit, thus improving the reliability of the seal, adapting to mass production, and enhancing overall performance.