Due to the complex flowing of the fluid inside the Hydraulic Manifold Block, the Computational Fluid Dynamics (CFD) method was applied to simulate the flow-field of the channels inside the Hydraulic Manifold Block. The numerical model of the channel was built according to the physical model, and it was solved by numerical method. The result indicated that the redundant technique-cavities had effect on the pressure-drop of the channel. The relation between the flow-field feature and the channel-structure was...