An embodiment of the present invention discloses a large-aperture wide-angle optical system. The optical system comprises the following parts from an object plane to an image plane along an optical axis: a first lens, a diaphragm, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. In addition, an embodiment of the present invention further provides a camera module. The large-aperture wide-angle optical system mainly comprises six lenses, so that the optical system has a small quantity of lenses, a simple structure, and low costs; and the diaphragm is between the firstlens and the second lens, which helps to shorten a front end aperture, so that an overall shape is moderate. In addition, the diaphragm is disposed near the front, different lenses are combined with each other, and a focal power is reasonably assigned, so that the optical system has optical performance such as being large in bore diameter, high in resolution, large in aperture, and good in athermalization, and is suitable for the automotive lens field.