The invention discloses a method for inhibiting calcium and magnesium in a mineral separation process. According to the method, zinc in zinc ores is separated by flotation in a form of zinc concentrate with a flotation process for 'roughing, scavenging and concentrating'; the method is characterized in that a combined reagent for inhibiting calcium and magnesium is added during concentration; the combined reagent is added as a calcium and magnesium inhibitor in the mineral separation process, the zinc concentrate containing relatively little calcium and magnesium is produced, inhibited calcium and magnesium are discharged along with tailings, and new slag or sewage is not generated; and the calcium and magnesium content of the zinc concentrate is greatly reduced, so that the difficult problem of calcium-magnesium open circuit in wet zinc hydrometallurgy production is solved, the zinc, germanium and sulfur grades and yields of the zinc concentrate can be all increased, and the transport cost of the zinc concentrate is reduced while the production value is increased.