Through the milling test of titanium alloy TC21, the surface roughness is measured with different cutting
parameters. Orthogonal experimental design method is used to arrange the test and range analysis to process experimental
data,and the effection to surface roughness caused by different cutting parameters, is analyzed. The most
significant effect on the TC21 titanium alloy surface roughness of the factors is the feed per tooth, followed by the cutting
depth and cutting speed,and the least important comes to cutting width. Based on the analysis of the mechanism of
effect on surface roughness, smaller amount of feed and cutting depth ,larger cutting speed and cutting width should
be used in processing