For the rapid manufacturing of thin-wall parts, the process experiments of selective laser melting (SLM) have been carried out on Dimetal-280 system. The influence factors such as laser power, scanning speed, powder preparing setting, defocus length and powder layer thickness are experimented and analyzed, then a group of optimal process parameters have been gotten. In the experiment, a variable cross-section thin-wall part with density of 96.95% has been produced. The result shows that the metallurgical bonding layer by layer is excellent in the thin-wall part when investigated in scanning electron microscope; It is shown that the minimum absolute error in the wall thickness of manufacturing parts using the SLM equipment is about 20 μm. The top and bottom thickness of the SLM part wall are 101.3 and 142.0 μm, respectively, and the differences between designed and SLM part are 21.3 and 22.0 μm, respectively, which are identical with the minimum absolute error. Tensile strength test shows that the tensile strength is 465~625 MPa, yield strength is 390~515 MPa, and elongation is 23%~48%.