An optical lens includes a first lens group with negative refractive power, a second lens group with positive refractive power, and an aperture stop disposed between the first lens group and the second lens group. A total number of lenses in the first lens group is less than three, and a total number of lenses in the second lens group is less than five. The second lens group includes a first lens, a second lens and a third lens arranged in order in a direction away from the aperture stop. Each of the first lens and the second lens is an aspheric lens, and one of the first lens and the second lens has a diffractive optical surface.