The invention relates to a low-temperature concrete early strength agent, which belongs to cement additives. The early strength agent consists of sodium metaaluminate, sodium silicate, sodium sulfate, sodium carbonate, lithium carbonate, lithium bromide, alkali metal chlorides, alkali metal hydroxides, zinc fluosilicate, magnesium fluosilicate, sodium fluosilicate, calcium fluoride, triisopropanolamine, a filtrate reducer, beta-naphthalene formaldehyde sulfonate polycondensate, ultrafine powder SiO2, ultrafine powder Al2O3, ultrafine powder Fe2O3, ultrafine powder CaO and ultrafine powder MgO. The early strength agent is mainly applied to winter concrete construction or low-temperature environmental emergency projects; when the early strength agent is used, the composition mixture is added into concrete according to 2 to 5 percent of the total weight of cement, water is added and then stirring is performed; and a cement block with the strength of 13.5MPa can be formed in a low-temperature environment at the ambient temperature of approximately 4 DEG C within 12 hours, a cement block with the strength of 18.5MPa can be formed within 24 hours and a cement block with the high strength of 30MPa can be formed within three days.