In order to explore machining characteristics of the soft abrasive flow field in a structured mold surface, the Single Dynamics Model(SPD) was applied to the solution to the motion characteristics of particles in different types of turbulence fields numerically. By taking a U-shaped flow passage for an example, the velocity and pressure of fluid in a two-phase soft abrasive flow field were solved by using the N-S equations,a Realizable k-ε model of turbulence and the SIMPLEC method. Then the velocity, locus and the density of particles in the two-phase field were also obtained by the SPD model. The results are that when the initial fluid velocities are 5, 10 and 20 m/s, the particle deposition is the largest for the first case. When the particle diameters are 0.01, 0.05 and 0.1 mm, the first value causes the particle deposition to be most obvious. In turbulence fields with different viscosities,the water, gas-oil and engine-oil show similar two-phase soft abrasive flow characteristics. It concludes that the initial velocity of the fluid field and the diameters of particles have more severe effect on the moving characteristics of particles,and the viscosity of the fluid influences them the least.