The present disclosure relates to a polymer film comprising a polyvinyl acetal resin and a plasticizer, wherein the polymer film comprises at least one first layer and at least one second layer, and the loss factor of the first layer and the loss factor the second layer are different; furthermore, the ratio of the loss factor of the first layer to that of the second layer is 1.30 to 3.12. The polymer film provided herein has an improved sound insulation effect.