We have developed a unique approach for the fabrication of enzyme coating on the surface of electrospun polymer nanofibers. This approach employs covalent attachment of seed enzymes onto nanofibers, followed by the glutaraldehyde treatment that crosslinks additional enzymes onto the seed enzyme molecules. These crosslinked enzyme aggregates, covalently attached to the nanofibers via seed enzyme linker, would improve not only the enzyme activity due to increased enzyme loading, but also the enzyme stability. To demonstrate the principle of concept, we fabricated the coating of alpha-chymotrypsin (CT) on the nanofibers electrospun from a mixture of polystyrene and poly(styrene-co-maleic anhydride). The addition of poly(styrene-co-maleic anhydride) makes it much easier to attach the seed enzyme molecules onto electrospun nanofibers without any rigorous functionalization of nanofibers for the attachment of enzymes. The initial activity of final CT coating was 17 and 9 times higher than those of simply-adsorbed CT and covalently-attached CT, respectively. While adsorbed and covalently-attached CT resulted in a serious enzyme leaching during initial incubation in a shaking condition, the CT coating did not show any leaching from the beginning of incubation in the same condition. As a result, the enzyme stability of CT coating was impressively improved with a half-life of 686 days under rigorous shaking while the half-life of covalently-attached CT was only 21 hours. This new approach of enzyme coating with high stability and activity will make a great impact in various applications of enzymes such as bioconversion, bioremediation, and biosensors.