A lens module includes a photosensitive chip, a hollow mounting frame, a filter, a lens holder, a lens, and a circuit board defining a first through hole and comprising a first surface and an opposite second surface. The photosensitive chip is installed on the first surface facing. The first surface includes electronic components and gold fingers installed thereon. One side of the photosensitive chip includes an electrical coupling portion electrically coupled to the gold fingers. The circuit board further includes an injection molding layer integrally formed onto the first surface. The injection molding layer seals the electronic components and the photosensitive chip therein. The mounting frame is fixed onto the second surface of the circuit board. The lens is installed within the lens holder. The lens holder is fixed onto a surface of the mounting frame facing away from the circuit board.