Abstract: Curved thin-walled parts have very important applications in the fields of spark micro - electrode and micro-turbine. In order to ensure the machining quality, the micro-milling of curved thin-walled feature has been studied to explore the influence of key parameters of feed engagement f_z, axial depth of cut a_p, radial depth of cut a_e and spindle speed n on such indicators as surface roughness Ra, size error Δ_w and burr width h in this paper, Based on the comprehensive balance method, the optimal milling parameters are obtained. The test results showed that n, f_z and a_p were the most influential factors for Ra, Δ_w and h respectively; The variable axial cutting process can inhibit the formation of burrs and obtain better processing quality. In order to improve the processing efficiency while ensuring the quality, larger radial depth of cut a_e and feed engagement f_z can be adopted in the processing process.