Abstract: On the basis of measuring PVA's weight loss and the change of dissolution rate of PVA size in water after plasma treatment at atmospheric pressure,a comparison of desizing between the plasma treatment and the traditional H₂O₂ method was made.XPS and FT-IR analyses of PVA films showed that plasma action led to some PVA molecules oxidized into some molecules such as CO₂,H₂O which disappeared in the air and the other part of PVA was oxidized and degraded to ones with shorter chains,thus increasing the swelling and dissolving properties of PVA size.