Ethylene vinyl acetate (EVA) was grafted with maleic anhydride (MAH) to get terpolymer of EVA-g-MAH, and then was employed as a reactive compatibilizer to develop PA11/PVC blends. Mechanical properties indicate the critical EVA-g-MAH content at about 15 wt% and the blending of PVC with PA11 reserves PA11s high performance even at high PVC incorporation. The glass transition temperature change by DMA proves the compatibilization effect. SEM micrographs reveal that PA11/PVC blends have a two-phase structure. Particularly, PA11 is the continuous phase and PVC is the dispersed phase. PVC disperses uniformly in PA11 phase in the presence of EVA-g-MAH, and the increasing PA11 content leads to further decrease of PVC domain size. PA11/PVC blends are compatibilized by in situ reaction between PA11 and EVA-g-MAH, as well as intermolecular specific interactions between EVA-g-MAH and PVC.