In view of the problems such as the poor selectivity,the high acidity,the time-consuming iron removal and the difficulty in resource utilization of iron by oxalic acid complexation-enhanced sulfuric acid leaching,the oxalic acid-sodium oxalate complex iron removal technology was proposed.The factors affecting the species distribution of Fe (Ⅲ),the relationship between its species distribution and the leaching effect of hematite,and the hematite removal conditions of oxalic acid-sodium oxalate were studied.The results show that the species distribution of Fe3＋in the leaching solution directly affect the leaching effect of hematite,and the pH  and n(C2O2-4)T/n (Fe3＋)T are the main factors affecting its species distribution.In order to improve the hematite removal effect,n(C2O2-4)T/n(Fe3＋)T should be at least greater than 3.0,and the leaching pH  should be kept near the minimum pH of Fe3＋ in the form of \[Fe(C2O4)3\]3-.As more than 95 % of iron is leached,gold,silver and metal sulfides are enriched in the leaching residue,and the iron in the leaching solution exists in the form of \[Fe(C2O4)3\]3-,sodium ferric oxalate can be prepared by evaporative and crystallization.This technology has the good iron removal effect,the high speed,and no wastewater discharge in the production process,it is a kind of efficient and clean production technology for treating cyanide tailings.