The invention discloses a method for modifying AB3 type hydrogen-storage alloy through polyparaphenylene. The method includes preparing AB3 type hydrogen-storage alloy by a vacuum induction melting process, crushing alloy ingots, subjecting the crushed alloy ingots to ball milling at the speed of 300 r/min for 60 minutes, and screening to obtain 300-mesh alloy powder; under protection of hydrogengas, adding benzene, catalyst AlCl3 and oxidant CuCl2 at the molar ratio 8:2:1 with stirring, raising temperature to 40 DEG C and then holding the temperature for 2 hours to obtain a product, cooling,filtering, washing and drying the product to obtain polyparaphenylene; uniformly mixing 96-99 parts by weight of alloy powder with 1-4 parts by weight of polyparaphenylene to achieve the purpose of modifying AB3 type hydrogen-storage alloy Mm<0.94>Mg<0.06>Ni<2.91>Mn<0.11>Al<0.04>Co<0.51> through polyparaphenylene. As polyparaphenylene having a certain corrosion resistant capacity is utilized formodifying the AB3 type hydrogen-storage alloy, both maximum discharge capacity and cycling stability of electrodes are improved.