The connection design of flow path is the most important task in Hydraulic Manifold Blocks (HMB) design. But the traditional method of feature design can not dynamically change the topology configuration and parameters of flow path when the design changed. This paper use a hybrid model consisting of temporary body model and B-Rep model, and represent flow path pattern using adjacency graph, adjacency matrix, weight matrix and degree array. The design parameters can be optimized by non-dominated sorting genetic algorithm (NSGA2). The topology configuration of flow path can adaptively change according to the design change.