The invention discloses a nitrite bacteria growth promoter including the components: 40-100 parts by weight, preferably 50-80 parts by weight, of metal salts; 5-30 parts by weight, preferably 10-20 parts by weight, of an amine substance; 0.05-1.5 parts by weight, preferably 0.1-1.0 part by weight, of organic acid hydroxylamine; and 10-40 parts by weight, preferably 20-30 parts by weight, of Na2SO3; the metal salts comprise a calcium salt, a magnesium salt, a ferrous salt and a copper salt, and the molar ratio of Ca<2+> to Mg<2+> to Fe<2+> to Cu<2+> is (5-15) to (5-25) to (1-8) to (0.5-5), preferably (8-12) to (10-20) to (2-6) to (1-4). The promoter has the advantages of simple formula and easy preparation, can be used in the cultivation process of nitrite bacteria, can also be directly added into a sewage treatment system, accelerates starting of short-cut nitrification-denitrification and short-cut nitrification-anaerobic ammonium oxidation processes and achieves stable operation.