The invention relates to a manufacturing method of a cross beam structure of a front bumper of an automobile. An inner layer is sleeved with an outer layer in such a manner that an outer layer front end plate is horizontally placed on an inner layer front end plate; two push plates are horizontally placed on outer layer inclined side plates in a one-to-one correspondence manner, and steel nails are inserted in rubber injecting hole forming guiding pits; an air storage chamber is inflated to drive a piston to move towards a rubber discharging chamber, so that rubber drives the push plates and the steel nails to move towards the outer layer inclined side plates; the push plates move towards the outer layer inclined side plates, so that inner layer inclined side plates are extruded, limitinggrooves are formed in the outer surfaces of the inner layer inclined side plates by the aid of skirt boards, and reinforcing ribs are formed on the inner surfaces of the inner layer inclined side plates; the steel nails move towards the outer layer inclined side plates, so that the rubber injecting hole forming guiding pits are pierced, and rubber injecting holes are formed in the outer layer inclined side plates; the rubber enters a cavity via the rubber injecting holes, and the inner layer and the outer layer are bonded together after the rubber is solidified. The invention provides the manufacturing method of the structure of the front bumper of the automobile. The method is used for manufacturing a cross beam of the front bumper of the automobile.