Abstract: As the largest melon vegetable planted in China, cucumber seedlings are vulnerable to drought stress during cultivation,and nano silicon can improve the resistance of many plants. Taking Jinchun No. 4 cucumber as an example, the effects of spraying nano-silicon on drought stress tolerance of cucumber seedlings were studied. The results showed that the leaf surface spraying of nano-silicon could significantly improve the phenotype of cucumber seedlings under drought stress, and increase the plant height, chlorophyll content and antioxidant enzyme activity.