The invention relates to a construction method for a rubble stone-ventilating board composite roadbed of an expressway at a permafrost area. The method includes the steps that firstly, rubble stone is prepared, after a bottom cushion layer is detected to be qualified, the rubble stone is poured for filling at a time, and then filling shaping, leveling and padding, and static pressure rolling are conducted; gravels are poured on the rubble stone for filling, after leveling and static pressure rolling, a water-permeable geotextile is laid on a gravel layer, and a sand-gravel cushion and a geogrid are laid on the water-permeable geotextile, so that roadbed construction is completed; a high-strength waterproof film is laid on the top face of a roadbed, pouring formworks for ventilating boards are mounted, a reinforcement fabric is manufactured, transverse PVC ventilating pipes are arranged, pouring is completed, and after top galling, curing and demolding are conducted. By means of the construction method, the temperature of the top surface of the rubble stone roadbed can be lowered, and the convection heat exchange effect inside the roadbed is enhanced; after the ventilating boards are additionally arranged on the rubble stone layer, the upper temperature of the rubble stone layer is lowered through the ventilation effect, the temperature difference between the top and the bottom of the rubble stone layer is increased, and the convection heat exchange effect of the rubble stone layer is enhanced.