The invention relates to an assembling mould for a car oil filler cap hinge, and the assembling mould provided by the invention comprises an upper mould, a lower mould, a crop convex mould, a crop concave mould, an upper reshaping pressing plate, a lower reshaping pressing plate, a cutting beating convex mould, a cutting beating concave mould, a beating convex mould, a beating concave mould, a moveable positioning mechanism, a positioning pin, and the like. A plurality of processes, such as shaft cutting, shaft baiting, hinge and shaft assembling, shaft beating, hinge forming, and the like, are simultaneously finished on one mould, thereby achieving the purposes of low cost, high efficiency and low energy consumption.