An exemplary optical lens group includes a first lens and a second lens. The first lens comprises a first central portion and an annular stepped portion. The annular stepped portion has a first outer step and a second outer step. The first outer step has a first outer side surface and a first downward-facing step surface. The second outer step has a second outer side surface and a second downward-facing step surface. The second lens comprises a second central portion and a peripheral portion. The peripheral portion has an inner side surface. The first lens is engaged in the second lens in a manner that the first outer side surface of the first lens is in contact with the inner side surface of the second lens. The second outer side surface of the first lens is spaced apart from the inner side surface of the second lens.