The invention discloses a method for drying a polyvinyl alcohol optical film. The method is characterized by comprising the steps that after a polyvinyl alcohol water solution is dry-molded and stripped from a curtain coating roller, the polyvinyl alcohol optical film is formed, a set of drying unit formed by one or more rollers is additionally arranged behind the curtain coating roller, and the polyvinyl alcohol optical film is made to enter the drying unit to be dried. The diameters, temperatures and speeds of all the rollers in the drying unit are adjusted, the heating strengths of the inner face and the outer face of the polyvinyl alcohol optical film are balanced, and the problems of warping and the too large width-direction phase difference caused by previous single-face heating are relieved or eliminated.