By using the method of orthogonal test design, the technology terms such as, peak value current, pulse width and intra pulse ratio in machining of WEDM of high speed running wire were optimized and designed experimentally. The electrical parameters were optimized by taking the machining speed of machine and surface roughness of parts as the goal. Aimed at these two indicators were different in nature, the dimensionless processing was done for them respectively to make both of them transferred to larger-the-better characteristic. In considering the different importance of these two indicators, the weighted mean method was used to transform the problem into a single objective problem so as to realize the optimization of electrical parameters. The results show that this method is feasible. The optimal values of machining parameters such as peak current, pulse width and intra pulse ratio are 24 A, 12 μs and 3 respectively.