Abstract: The low-Co MlNi_4.57Co_0.17Mn_0.25Al_0.41Y_0.02 hydrogen storage alloys with long life were prepared using vacuum induction melting method.Annealing was carried at different temperatures(1040 ℃, 1060 ℃, 1080 ℃) and insulation for 5 h, 7 h and 10 h, respectively.The effects of different annealing processes on the microstructure and electrochemical properties of the alloys were studied. The results show that annealing is beneficial to the uniformity of the alloy composition and the elimination of lattice stress.With the increase of annealing temperature and holding time, the isothermal equilibrium pressure of PCT curves for hydrogen absorption and desorption increases gradually, and the cycling stability of the alloys increases significantly. The maximum discharge capacity and high rate discharge performance of the alloys decrease, and the effect of annealing temperature on the electrochemical performance of the alloy is stronger than that of holding time.After annealing at 1060 ℃ for 10 h, the maximum discharge capacity of the alloy is 332.8 mA·h/g, and the cycles of 80% capacity retention rate can reach 349 times. The alloy has the best overall electrochemical performance.