The invention provides an anti-efflorescence sea water coral aggregate concrete block. The anti-efflorescence sea water coral aggregate concrete block is prepared from sea water coral aggregate concrete, wherein the sea water coral aggregate concrete is composed of the following raw materials in percentage by mass: 7-11% of silicate cement, 3-4.5% of sea water coral aggregate concrete salt fixing agent, 5-7.5% of sea water and 77-85% of coral reef sand aggregate mixture; the doping amount of sea water concrete water-reducing agent accounts for 0.2-0.4% of the mass of a cementing material; and the cementing material is a mixture of the silicate cement and the sea water coral aggregate concrete salt fixing agent. The sea water coral aggregate concrete block has the advantage of realizing long-term service with no efflorescence and good durability on oceanic island reefs in China and under other severe natural environments; in the molding and curing period, the sea water coral aggregate concrete block can realize three NO NEEDS, i.e. no need of sinter molding, no need of autoclaving and no need of fresh water maintenance; and meanwhile, the sea water coral aggregate concrete block has the characteristics of low comprehensive cost, greenness, energy saving, high efficiency and the like.