The invention relates to a method for improving the content of ferrous iron in leaching liquid during the zinc oxide smoke and dust leaching process, and belongs to the field of zinc hydrometallurgy.The method comprises the steps that in the second-stage acid leaching process of zinc oxide, first-stage acid leaching bottom flow is guided into a second-stage acid leaching 1# reaction tank and a second-stage acid leaching 2# reaction tank, roasted dust and waste electrolyte are added into the second-stage acid leaching 1# reaction tank, roasted sand leaching acid bottom flow, sulfur concentrateand concentrated sulfuric acid are added into the second-stage acid leaching 2# reaction tank, full reaction is conducted, then mixing is conducted, and a mixture is guided into a second-stage acid leaching 3# reaction tank for further reaction, obtained high-iron second-stage acid leaching ore pulp is filtered, so that lead slag and high iron liquid are obtained; and the high iron liquid returnsto a first-stage acid leaching process for first-stage acid leaching iron supplement. Through the method for improving the content of the ferrous iron in the leaching liquid during the zinc oxide smoke and dust leaching process, the content of Fe2+ in the high iron liquid is improved to 16000-22000 mg/L, so that it is ensured that the content of first-stage acid leaching Fe2+ is stably controlledto be 5000-6000 mg/L, and smoothing carrying out of the neutralizing and impurity removing process of subsequent stages is ensured.