The invention relates to polyurethane dampproof vapor insulation paint for a cold storage warehouse and a preparation process thereof, is particularly applicable to water proofing and damp isolation of a heat insulation layer of a cold storage warehouse, and belongs to the technical field of polyurethane waterproof materials. The polyurethane dampproof vapor insulation paint is prepared from the following raw materials in parts by weight: 20 to 70 parts of combined polyether polyols, 10 to 50 parts of isocyanate, 2 to 20 parts of plasticizers, 0 to 0.5 part of catalysts, 0 to 2 parts of stabilizing agents and 10 to 50 parts of solvents. The preparation process comprises the following steps that 1, the combined polyether polyols are subjected to dewatering for 2h at 100 to 120 DEG C and -0.08MPa to -0.1MPa in a vacuum state; the temperature is lowered to 40 to 60 DEG C; 2, the plasticizers, the solvents and the isocyanate are sequentially added; reaction is performed for 3 to 4h at 60 to 70 DEG C; 3, the catalysts and the stabilizing agents are added; after uniform stirring, the temperature is lowered to room temperature; discharging is performed. A cured coating has high bonding force, excellent mechanical performance and good dampproof vapor insulation performance; the construction is convenient.