The work aims to prepare undoped diaphragma juglandis carbon dots (1-CDs)/PVA composite films and nitrogen-doped diaphragma juglandis carbon dots (2-CDs)/PVA composite films with different concentrations of carbon dots to extend the shelf life of strawberries. The composite films were prepared by tape casting and the effects of different concentrations of CDs on photoluminescence, hydrophobicity, UV absorption and barrier properties of the composite films were studied. The preservation effects of different films on strawberry were compared. The strong intramolecular or intermolecular interaction occurred between carbon dots and PVA. The addition of carbon dots enhanced the hydrophobicity and UV absorption properties of the composite films. The contact angle of 2-CDs/PVA-6 composite film at 60 s was 65.3°, the elongation at break and the tensile strength were (220.6±6.3)% and (107.55±4.9)MPa, respectively. The ultraviolet and visible light transmit of 2-CDs/PVA-6 composite film was close to 0 at 300 nm wavelength. The composite film had the best preservation effect on strawberry. As a packaging material, 2-CDs/PVA-6 composite film shows the potential to extend the shelf life of strawberries.