An optical lens includes a first lens body having a first light exiting surface, a second light exiting surface, a first light incident surface, a second light incident surface, a third light incident surface, and a bottom surface connected to the light incident surfaces; a second lens body having an outer circumference surface, a first inner circumference surface, and an uneven second inner circumference surface; and a mounting body surrounding and connected to the first and second lens bodies, and extending outward with respect to the first and second lens bodies. The first, second and third light incident surfaces are sequentially connected to form on the bottom surface a groove for receiving a light emitting unit. The optical lens has a horizontal beam angle equal to 171.6 degrees ±10% and a vertical beam angle equal to 160 degrees ±10%.