Abstract: In this paper, 2197 Al-Li alloy was mechined by the chemical milling, and the influence exerted on milling rate and surface roughness of 2197 Al-Li alloy by composition of chemical milling solution and temperature were investigated. The influence of original surface roughness on chemical milling quanlity was discussed. The results show that the milling rate increased with the temperature of chemical milling solution and the NaOH solution concentration increased. The milling rate decreased with the concentration of Al3+ increased. Surface roughness increased obviously with the increasing of milling depth, and when the milling depth was more than 3.6 mm, the surface roughness changed little. The surface roughness of the chemical milling sample after chemical milling increased with the increase of the original surface roughness of the sample.