A lens includes a light incident surface and a light exiting surface. The light exiting surface includes a first concave surface, a first convex surface, a second convex surface, a first curved surface, and a second curved surface. The first concave surface is located at the center of the light exiting surface for diverging the light exiting therefrom. The first and second convex surface are arranged at two opposite sides of the first concave surface respectively for converging the light exiting therefrom; the first convex surface, the first concave surface, and the second convex surface connect in sequence along a first direction. The first and second curved surfaces are arranged at another two opposite sides of the first concave surface respectively; the first curved surface, the first concave surface, and the second curved surface connect in sequence along a second direction perpendicular to the first direction.