In this paper, we designed the Y-type and T-type micromixer based on generalized Murray's law. We studied the influence of geometric parameters and pressure drop on mixing efficiency and analyzed the concentration curves of fluid at the outlet. The influence of geometric parameters on mixing performance is studied by using COMSOL Multiphysics 5.2a. The number of hierarchical levels can have a significant effect on mixing efficiency and the more of the levels, the higher of the mixing efficiency. For Y-type micromixer, the influence of different branch angles alpha = 30 degrees, 60 degrees, 90 degrees on the mixing efficiency was analyzed, and the 30 degrees Y-type micromixer has the best mixing performance. The micromixer designed in this paper has a high mixing efficiency of over 90% in the range of Re 0.5-100. The generalized Murray's law can be widely used in the design of micromixers. (C) 2019 Elsevier Ltd. All rights reserved.