An optical lens includes five aspheric lenses and an aperture stop. The five aspheric lenses are, arranged in order from a first side to a second side, a first lens, a second lens, a third lens, a fourth lens and a fifth lens, and the aperture stop is disposed between the first lens and the second lens. An image height at the image plane is denoted as H, the image height is equally divided into ten sections to from ten height positions 0.1H, 0.2H, 0.3H, 0.4H, 0.5H, 0.6H, 0.7H, 0.8H, 0.9H and 1H. Chief rays traveling through the optical lens and to the ten height positions respectively form ten angles with respect to a normal of an image plane, and each of the ten angles is smaller than 10 degrees.