The invention discloses masonry mortar for an underwater acid environment. The masonry mortar comprises, by weight, 180-220 parts of common cement, 30-50 parts of special cement, 695-705 parts of natural medium sand, 20-30 parts of resin adhesive powder and 30-40 parts of special additives, wherein the special additives are mixed by, by weight, 2-5 parts of thickening agent, 0.5-1 part of super plasticizer, 5-8 parts of thixotropic agent, 12-15 parts of thickening time control agent and 5-8 parts of early strength agent. The masonry mortar has the advantages that by regulating the additives special for high-performance underwater masonry mortar and adding resin materials good in acid resistance, masonry mortar components are prevented from have reaction under acid conditions, the hardening and performance of the mortar cannot be affected, and the masonry mortar is less prone to dispersing, good in constructability, resistant to acid, capable of being normally hardened under water and high in strength under water operation conditions.