Hydraulic valve block is an important part of aviation Electro-Hydrostatic Actuator (EHA). With the development of EHA in the direction of light weight and integration, the internal flow channel of the hydraulic valve block is required to be more compact. Based on the technical means provided by additive manufacturing technology, this paper adopts the Ant Colony Algorithm + B-spline curve to design the internal flow channel of the aviation EHA valve block, and realizes the automatic arrangement of the flow channel by computer. The flow characteristics of the flow channel before and after optimization are analyzed. The volume of the flow channel after optimization is reduced by , besides the pressure loss measured by the test is reduced by to . The feasibility of optimizing the design of flow channel by Ant Colony Algorithm and B-spline curve is verified, which provides a solution for flow channel design method based on additive manufacturing.