In this paper, the type of obstacle micromixer model was designed and investigated by numerical simulation to improve the mixing efficiency. Passive mixers with tail-added obstacles structures were studied and compared with other conventional T microstructures, and then their mixing performance was numerically evaluated. The micro-T mixer with tail-added obstacles (µTTAO) exhibited a higher mixing efficiency and reached 87.2%. In addition, the concentration range at the outlet was also narrow, the mixing efficiency was increased by about 1.41 compared with the normal micro-T mixer. The combination of grooves greatly enhances the mixing in the flow path due to strong turbulence. The combination of multiple tracks in the fluidic structure enhances the micromixer's performance by reducing mixing time. In addition, the influence of the length and number of obstacles in the microchannel has also been studied extensively. This study shows that increasing the number or length of obstacles in the microchannel optimally improves the mixing efficiency value. The results further demonstrated that going beyond the performance of the micro-T mixer with obstacles, the µTTAO is a potential structure for optimizing the mixing quality of the micro-T mixer. This study is a significant turning point with high efficiency and low cost in the future.