The invention relates to a machining technology of a thin-wall sleeve with surfacing hard stellite. The machining technology comprises steps as follows: blanking, heat treatment, size processing before turning and welding, mounting of a welding support device, welding, mounting of a coarse grinding tool for coarse grinding of welding position excircle, semi-finish turning as well as mounting of amandrel device for accurate grinding and finish turning. With the adoption of the welding support device, the coarse grinding tool and an accurate grinding tool, welding quality is guaranteed, the problems of welding cracks and large deformation in conventional welding process are solved, the heat treatment is performed after welding, stress produced by welding is eliminated, a shaft sleeve blankis subjected to heat treatment, mechanical properties of materials are guaranteed, the problem of deformation of the shaft sleeve in the grinding process of the conventional shaft sleeve with thinnerwall is solved, and machining precision is greatly improved.