The invention discloses a back plate for a photovoltaic cell, which comprises an inner surface layer, an intermediate layer and an outer surface layer from the inside to the outside, the outer surface layer is made of a modified polyamide resin composition, and the modified polyamide resin composition It includes the following components, polyamide resin, graft polymer resin, functional filler, additive; the functional filler is a layered silicate clay modified by isobutylamine polyhedral oligomerization silsesquioxane; the intermediate The layer is made of a modified polypropylene resin composition; the modified polypropylene resin composition includes the following components: polypropylene resin, grafted polyethylene resin, cage polysilsesquioxane, and additives. The bonding performance between the back sheet and EVA, the aging resistance performance and the water vapor barrier performance of the present invention are all very excellent, can fully meet the service life requirements of the solar battery module, obtain remarkable effects, and have positive practical significance.