The orthogonal test of two dimensional ultrasonic extrusion 7075 aluminum alloy were carried out. The comprehensive influence of process parameters on the surface roughness and micro hardness were studied with grey relational analysis. The prediction model of the grey relational degree was constructed with the multiple linear regression method.The optimal process parameters were determined based on the prediction model. The results indicate that the influence of the process parameters on the surface roughness, micro hardness and gray relational degree are different, and process parameters obtained by ranking the grey relational degree are not the optimal value. The prediction model of grey relational degree can accurately forecast the test results, and the optimal process parameters obtained by the nonlinear programming solver based on the model. When the static force is 220 N, the extrusion speed is 30 m/min and the feed-rate is 0.14 mm/r,the optimal surface quality may be obtained with the surface roughness of Ra 0.44 μm and the microhardness of 637 HL.