Inorganic nanoparticles have demonstrated significant applications in biomedicine field, whose biomedical functions and physicochemical properties are greatly influenced by their size and morphology. However, it still remains challenging to achieve high batch-to-batch reproducibility in the synthesis of inorganic nanoparticles with traditional batch synthesis methods. Meanwhile, microfluidic technology offers an advanced strategy that provides high controllability and repeatability for the synthesis of inorganic nanoparticles. Additionally, it facilitates rapid mass and heat transfer, while offering the advantages of small reaction volumes and low energy consumption, rendering it an ideal approach for the synthesis of inorganic nano-biomaterials. This article reviews the research and application progress of microfluidic technology in preparation of inorganic nano-biomaterials. Firstly, flow regimes and principles of mixing in the microfluidic devices are introduced. Subsequently, structural features and fluid mixing efficiency of five widely studied and applied microfluidic devices are presented. Importantly, applications of these microfluidic devices in synthesis and surface modification of inorganic nanoparticles are comprehensively summarized. Finally, this article briefly outlines challenges and potential opportunities for future developments in microfluidic-based synthesis and application of inorganic nano-biomaterials.