The invention discloses a construction method for additionally laying an asphalt layer after treatment of a concrete pavement under the high cold and heavy load conditions. The method includes the steps of 1, performance detection and repair of an old pavement, wherein cracks with the deflection value smaller than 20 (0.01 mm) are repaired with pouring sealant, cracks with the deflection value being 20-45 (0.01 mm) are repaired with cement grout, and plates with the deflection value larger than 45 (0.01 mm) are replaced; 2, reinspection after repair, wherein the pavement is not up to standard unless the deflection value is smaller than 20 (0.01 mm); 3, pavement cleaning; 4, joint reinforcement, wherein glass fiber grids are connected to the two sides of joints in a lap joint mode; 5, additional laying of an asphalt macadam layer, wherein the asphalt macadam layer is additionally laid with the asphalt and macadam synchronization technology; 6, stable rolling, wherein when the temperature of the asphalt macadam layer is lowered to the degree that a steel-wheel road roller does not take away macadam due to adhesion, stable rolling is carried out with the steel-wheel road roller; 7, curing, wherein after the asphalt macadam layer is laid, curing is carried out; 8, surface course construction, wherein after curing, a surface course asphalt mixture is laid.