The invention discloses a car lamp light adjusting screw and a manufacturing method thereof. The car lamp light adjusting screw is of an integrated columnar structure and comprises a screw head, a screw rod and a thread. The screw head is arranged at one end of the screw rod. The thread is arranged on the screw rod. An inner cross and an inner hexagon are formed in the screw head. Gears are arranged on an outer circle of the screw head. A buckle is arranged on the screw rod and connected with the screw rod into a whole. A concave ring groove for mounting a sealing washer is formed in the screw rod. A limiting ring is arranged on the screw rod. According to the manufacturing method of the car lamp light adjusting screw, a mold is manufactured according to the structure of the car lamp light adjusting screw to be manufactured, the one-time injection molding method is adopted, and the car lamp light adjusting screw is manufactured through demolding. The car lamp light adjusting screw adopts the integrated design and is free of splicing and assembling components, the effect that the whole screw rotates coaxially during car lamp light adjusting can be ensured, and the car lamp light balance adjustment is ensured; and meanwhile, the inner cross and the inner hexagon are formed in the screw head, the gears are arranged on the outer circle of the screw head, and various car lamp adjustment modes, namely a manual mode, an electric mode and a dynamic mode can be achieved.