In order to study the dynamic characteristics of multi-cutting electrode wire, its spatial mechanics model is established by analyzing the stress condition of electrode wire in the dielectric fluid, and a fluid-solid coupling nonlinear vibration model is established by joining wire electrode additional axial force that is caused by wire vibration, and the four order Runge-Kutta method is employed to obtain the motion trajectory of electrode wire center. Based on these, the conclusion is obtained that the direct cause of the actual correction reducing is electrode wire migration caused by unilateral discharge. According to Einstein two phase fluid viscosity theories, the relationship between the scrap particle volume concentration and two phase fluid drag coefficient is obtained. Simulation results show that the velocity of dielectric fluid has a great effect on electrode wire dynamics, and even it can cause flutter instability phenomenon. At last, the influences of machining parameters on the machining precision are discussed.