Abstract: Micromixer is an important part of microchip integrated system, widely used in biological analysis, chemical synthesis and other fields. In order to improve the mixing efficiency of passive micromixers under low Reynolds number laminar flow conditions, a serpentine channel micromixer with herringbone ridges was designed in this paper, and its mixing structure and fluid parameters were analyzed. Based on the study on the effect of herringbone ridges height and angle on fluid mixing, the influence of flow rate on mixing effect was analyzed when the herringbone ridges angle θ = 45° and d/H was 1/2. At the same time, PBS solution and Trypan blue dyeing solution were selected for experimental tests to comprehensively evaluate the mixing performance of the micromixer. The results show that, in a certain range of structural parameters, the greater the ratio of herringbone height to channel height, the more sufficient the fluid mixing, and the optimal herringbone angle is between 40° and 50°. The lower the flow velocity, the higher the mixing quality. The average error of simulation and experiment is less than 10%. This study provides a reference for improving the mixing efficiency of passive micromixers.