The influence of affecting factors on the oxidation rate of (NH₄)₂SO₃ including concentration of (NH₄)₂SO₃, concentration of (NH₄)₂SO₄, temperature, pH value, air flow rate and concentration of CoSO₄ were studied. The results showed that the oxidation rate of (NH₄)₂SO₃is lowered with the increase of initial concentration of (NH₄)₂SO_3. It is the same as concentration of (NH₄)₂SO₄. From 40 ℃ to 60 ℃, (NH₄)₂SO₃ oxidation rate increases with the increase of reaction temperature. The (NH₄)₂SO₃ oxidation rate is also influenced by the pH value of the mixed solution, with the most preferred value being 5.5. When the air flow rate is within 100~400 L/h and with increase of air flow, (NH₄)₂SO₃ oxidation rate increases. Taking into account the ammonia desulfurization project, the most appropriate process parameters are: reaction temperature at about 50 ℃, (NH₄)₂SO₃ at low concentration, the pH value of mixed solution at 5.5, air flow rate at 300 L/h and CoSO₄ at high concentration.