Disclosed are a polyvinyl alcohol film and a preparation method therefor. The saturated water absorption of the amorphous structure in the polyvinyl alcohol film is x, the water absorption increased due to destruction of the crystal surface defect structure in the polyvinyl alcohol film is y, and x/(x+y) is 0.82 to 0.93. The polyvinyl alcohol film has a softening point of 65 C. to 75 C., and a degree of swelling of 180% to 220%.