Polydimethylacrylamide (PDMA) microgels and niobate nanosheet/PDMA composite microgels were fabricated by using a microfluidic device. Morphologies and sizes of the composite microgels were tuned by adjusting synthetic conditions such as viscosity of oil phases, hydrophilicity and concentration of surfactants, and flow rates of oil phase and water phase. Furthermore, it was found that the dispersion of nanosheets was better when the composite microgels were synthesized by photopolymerization compared to redox polymerization.