The invention relates to a method for treating the surfaces of PVC (polyvinyl chloride) sections. The method includes steps of 1), cleaning sundries and dust on the PVC surfaces, peeling protective films on the surfaces of the PVC sections, wiping the PVC surfaces required to be painted and drying the PVC surfaces; 2), treating all the certain PVC surfaces by the aid of primer paint with viscosity; 3), sufficiently stirring or shaking coatings before the coatings are used, thoroughly cleaning and drying spraying tools, spraying the coatings on the PVC surfaces by the aid of the spraying tools straightaway once solvents for cleaning the spraying tools are volatilized during cleaning, and adjusting the sizes of spray nozzles so that the sizes of the spray nozzles range from 1.5mm to 2.0mm; 4), spraying water-based oil paint on the surfaces of the sections, and keeping the distances from spray guns to the sections to range from 15cm to 20cm during spraying; 5), drying the surfaces of the PVC sections. Colors need to be sprayed on the certain PVC surfaces which are treated by the aid of the primer paint with the viscosity. The thicknesses of wet paint films formed after the water-based oil paint is sprayed on the surfaces of the sections range from 30 micrometers to 50 micrometers. The method has the advantages that a processing technology for spraying water-based paint on the PVC surfaces can be improved, spraying operational steps are detailed, operation is simple and can be easily understood, and the service life of the water-based oil paint can be effectively prolonged.