Before plastic film mulching. According to the query of China Agricultural Network, pruning should be completed before plastic film mulching. Under normal circumstances, it will be carried out 20 days after the temperature drops obviously and all the grapes have fallen leaves. Beware of cutting early in winter, but cut late to enhance the frost resistance of grapes. Pruning should be done before plastic film mulching, but be careful not to be too late to avoid wasting a lot of nutrition because of bleeding.