The geometric effect of microfluidic channels on the production of monodispersed alginate hydrogels was investigated. The general flow focusing design could not produce stable hydrogels because the synthesis between alginate and calcium chloride at the Junction strongly depends on the diffusion limited reaction. The addition of winding microchannels as a mixing line could not perfectly solve the diffusion problem because imperfect mixing of alginate and calcium solutions results in unstable generation of alginate microbeads and merging of the produced alginate beads in the microfluidic devices. The last microfluidic design adopted a mechanism in which the droplet formation was based on a biased shear-force-driven break-off to improve rapid draplet formation and mixing efficiency. The final design of microfluidic device could promptly produce the stable monodispersed-hydrogel beads.