The invention relates to a metamorphite machine-made sand concrete capable of inhibiting alkali activity of metamorphite aggregate, which comprises 100 parts of cement, 10-60 parts of fly ash, 0.05-0.8 part of lithium compound, 0.1-2.0 parts of silane, 0.5-4 parts of water reducing agent, 0.005-0.07 part of air entraining agent, 190-480 parts of fine aggregate, 200-480 parts of coarse aggregate and 30-80 parts of water. The preparation method comprises the following steps: after mixing the cement and silane, adding the coarse aggregate, fine aggregate, fly ash, lithium compound and air entraining agent, continuing the dry mixing, dissolving the water reducing agent in water to obtain a water solution, adding the water solution, and continuing stirring to obtain the metamorphite machine-made sand concrete. By using the metamorphite machine-made sand and metamorphite gravel as aggregate, the invention fully utilizes the environmental resources, greatly lowers the manufacturing cost of concrete engineering, and reduces the environmental load; and the prepared concrete product has obvious inhibiting effect on alkali-aggregate reaction of the metamorphite concrete with alkali activity.