This work is focused on the I-lancing performance in passive microchannels. Experiments are performed to investigate the effect of inlet mixing angle and surface wettability on the micromixing efficiency in micromixers. The iodate iodide testing reaction and a micro particle image velocimetry (micro-PIV) system are adopted to characterize the micromixing efficiency. The results demonstrate that the micromixing efficiency is enhanced as the inlet mixing angle increases. It is also illustrated that the mixing performance in hydrophobic microchannels is better compared to hydrophilic ones. To optimize the Configuration of microchannels for better mixing, a novel baffled spiral micromixer is developed. The experiments show that the micromixing efficiency in the novel micromixer is significantly improved, compared to conventional ones.