Abstract:GH4169 superalloy deep hole parts are widely used in aerospace fields. There are some problems in machining GH4169 superalloy deep hole by traditional drilling method, such as serious tool wear, high cutting heat and low cutting efficiency. Mixed plasma machining is a kind of special machining method, which has the characteristics of zero cutting force and high machining efficiency. The mixed plasma machining can be used in the deep hole machining of GH4169 superalloy to solve the difficult problems. The peak current, spindle speed and electrode feed speed are important influencing factors in the deep hole machining of GH4169 superalloy by using mixed plasma, and the surface roughness and material removal rate are the performance indexes to measure the machining effect. Single factor and orthogonal experiment were used to control the test, and the obtained experimental data were analyzed by extreme value method and grey correlation degree. The optimal combination of test parameters was obtained as follows: When the peak current is 25A, the spindle speed is 75rad/min, and the electrode feed speed is 0.45mm/min, the measured material removal rate is 158.65mm3/min, and the surface roughness is 1.9μm. Compared with the drilling deep hole processing of GH4169 superalloy, the machining efficiency is greatly improved.