The invention relates to an engine coolant, which comprises the following compositions in portion by weight: 100 portions of glycol, 60 to 160 portions of deionized water, 1.0 to 1.6 portion of sodium benzoate, 1.0 to 1.4 portion of sodium tetraborate, 0.1 to 0.5 portion of sodium nitrate, 0.5 to 0.9 portion of phthalic acid, 0.3 to 0.6 portion of sodium silicate, 0.03 to 0.06 portion of silicate stabilizer, 0.3 to 0.4 portion of sodium hydroxide, 0.1 to 0.3 portion of pyrrodiazole, 0.01 to 0.06 portion of defoaming agent and 0.005 to 0.02 portion of coloring agent; the engine coolant is characterized in that: the coolant does not contain molybdate, amine, nitrite, phosphate and other substances which are harmful to the environment and human body and has excellent anticorrosive and protective function on red copper, brass, steel, cast iron, soldering tin, cast aluminum and other metals of a cooling system and magnesium alloy adopted in an engine; and the coolant has strong anti-hard water capacity and low cost, meets the requirement of SH/T0521-1999 standard and is applicable to industrialized production.