The invention provides a method for capturing and identifying fetal nucleated red blood cells in a microfluidic chip. The method comprises the following steps: 1, synthesizing gelatin nanoparticles bya two-step solvent removal method and preparing into a precursor liquid, and then introducing into a microfluidic chip to form a nanometer coating on the inner wall thereof, wherein the microfluidicchip comprises a plurality of serpentine main channels and the plurality of fish bone units; 2, modifying streptavidin on the nanometer coating by a chemical modification method, then grafting a biotin-modified antibody; 3, separating a mononuclear cell layer containing fetal nucleated red blood cells from peripheral blood by density-gradient centrifugation; 4, allowing mononuclear cell suspensionto flow into the microfluidic chip at a certain flow rate for capturing; 5, introducing a certain concentration of gelatinase into the microfluidic chip that captures fetal nucleated red blood cells,releasing fetal nucleated red blood cells by degrading the nanometer coating; and 6, identifying captured fetal nucleated red blood cells by using specific antibodies.