<p>Drug-loaded microspheres have garnered increasing attention in drug delivery systems due to their excellent drug-loading capacity and controlled-release characteristics. The performance of these microspheres is critically influenced by both the encapsulated drug and the physicochemical properties of the microspheres themselves, thereby affecting drug administration efficiency. Although conventional microfluidic chip systems are effective in generating monodisperse droplets, producing droplets with varying drug concentrations typically requires additional micro-mixing post-generation. Such mixing often relies on specialized microstructures or external forces, which can lead to droplet fragmentation and instability. Moreover, inefficient mixing during this stage may cause substantial drug loss during subsequent crosslinking reactions. To address these challenges, a concentration gradient microdroplet chip specifically designed for drug microsphere preparation was developed. The chip enables stable formation of concentration gradients within the drug solution, followed by the generation of gradient droplets. Crosslinking reactions subsequently yield drug-loaded hydrogel microspheres. This chip demonstrates the ability to precisely control both concentration and particle size of the microspheres, offering a robust and efficient platform for investigating optimal parameters for sustained drug release.</p>