Disclosed is a polyalkylene carbonate and polyolefin-based composite and, more particularly, a composite prepared through reaction of a mixed composition including polyalkylene carbonate, polyolefin, an initiator, and a blending aid, wherein an amount of the polyalkylene carbonate is 60 wt % to 95 wt %, a total amount of the initiator, the blending aid, and the polyolefin is 5 wt % to 40 wt %, and the composite has a matrix-filler morphology in which a matrix formed of the polyalkylene carbonate includes a filler formed of the polyolefin.