The invention provides a lens module. The effective focal length of the lens module is a positive value, the lens module comprises a first lens, a second lens and a third lens which are mutually fitted, the first lens is a positive focal length lens, the side surface of the first lens close to an eye to be detected is a concave surface, the side surface of the first lens far away from the eye to be detected is a convex surface, the second lens and the third lens are of gluing structures, the side surface of the second lens close to the eye to be detected is a convex surface, and the side surface of the third lens far away from the eye to be detected is a concave surface. Compared with the prior art, the lens module has the advantages that a first lens module can effectively compensate axial and vertical axis color difference of the eye to be detected, an imaging plane of the lens module has better imaging effect, the lens close to one side of the eye to be detected is a concave surface, the curvature radius of the surface is properly set, and obvious stray light cannot be introduced into imaging results even if the surface has smudge.