Abstract: The present invention relates to a hydrogen storage alloy, an electrode for a Ni-MH battery, a secondary battery, and a method for preparing the hydrogen storage alloy. The chemical composition of the hydrogen storage alloy is expressed by the general formula La(3.0˜3.2)xCexZrySm(1-(4.11˜4.2)x-y)NizCouMnvAlw, where x, y, z, u, v, w are molar ratios, and 0.14?x?0.17, 0.02?y?0.03, 4.60?z+u+v+w?5.33, 0.10?u?0.20, 0.25?v?0.30, and 0.30?w?0.40. The atomic ratio of the metal lanthanum (La) to the metal cerium (Ce) is fixed at 3.0 to 3.2, which satisfies the requirements of the overcharge performance of the electrode material. A side elements are largely substituted by samarium (Sm) element, that is, the atomic ratio of Sm on the A side is 25.6% to 42%, so as to solve the problem of shortened cycle life caused by the small amount of cobalt (Co) atoms.