The present application discloses a selective leaching method for a nickel-iron alloy and a method for preparing a high-purity nickel salt are disclosed, wherein the selective leaching method for a nickel-iron alloy comprises the following steps: using a nickel-iron alloy powder to prepare into a slurry, adding a combined reagent into the slurry to form a to-be-leached system, leaching the to-be-leached system at 30 ? or above and carrying out solid-liquid separation to obtain a leaching solution; wherein the combined reagent comprises an iron-containing solution, an oxidizing agent and an acidic reagent, or the combined reagent comprises an iron-containing solution, an oxidizing agent and a sulfur-containing reagent; the pH value of the to-be-leached system is 0.5-5.0, and the concentration of Fe ions is 2 g/L or more. According to the present application, through the mode of returning the leaching solution or adding the iron-containing solution, the dissolution of nickel is ensured, the dissolution of iron in the nickel-iron alloy powder can
be avoided as much as possible, the leaching rate of iron is reduced, further the neutralization reagent required in the subsequent nickel-iron separation can be effectively reduced, and the production cost is greatly reduced under the condition of ensuring the yield of nickel.