This article analyzes the factors that cause surface cracking during the drying process for parquet and the curing principle of polyurethane coating by ultraviolet irradiation method.To investigate how ultraviolet affected the coating quality,the authors arranged four experiments to dry red oak parquet by ultraviolet radiation under different intensity conditions.The coating qualities were examined in terms of the time to initiate cracking and total crack area.Great differences were found in coating quality among different parquets,which showed the importance of suitable irradiation power to ensure coating quality.