The invention relates to the field of building materials, in particular to a method for preparing a building cementing material from electrolytic manganese metal leaching residues. According to the method, the electrolytic manganese metal leaching residues are treated by adopting concentrated sulfuric acid; sulfate slag and acid-leached electrolytic manganese metal liquid are generated; by removing various metals from the acid-leached electrolytic manganese metal liquid, composite aluminum iron phosphate, copper-cobalt-nickel sulfide concentrate, manganese carbonate concentrate and ammonia water are effectively recovered and mixed with the sulfate slag, the mixture is reacted with calcium hydroxide generated by reacting quick lime and water, and mixed with Portland cement to generate the cementing material; the activity of the electrolytic manganese slag is improved, and the gelling property of the electrolytic manganese slag can be fully excited; the prepared building cementing material can be prepared into cement masonry mortar, plastering mortar, dry-mixed mortar, exterior wall plastering mortar, baking-free bricks and the like, the mixing amount of cement in the cementing material is reduced, the setting time of the cementing material can be adjusted, the strength is high, the cementing material is healthy and environmentally friendly, the cost is reduced, and the economicbenefits of enterprises are improved.