The influence laws of precision machining parameters on the cutting speed and surface roughness in MS-WEDM multiple cutting processes were investigated. Taking pulse width, interpulse, power amplifier and thread speed in the second and third cutting processes as the variables, multiobjective optimization related to the surface roughness and cutting speed was optimized to a single objective problem of weighted comprehensive score using comprehensive evaluation method. Orthogonal table L12(28) was selected to design the experiment, and the experimental data were analyzed using signal noise ratio method (SNR). The results show that the second cut with pulse width of 8 μs, interpulse of 5 μs, two amplifiers and cutting speed of 6 m/s, while the third cut with pulse width of 2 μs, interpulse of 4 μs, one amplifier and cutting speed of 3 m/s should be the desired finish machining scheme. Using such a scheme, a surface roughness about 119 μm and a cutting speed about 9960 mm2/min can be obtained.