In order to make better use of solar energy to convert carbon dioxide into value-added products, we synthesized hexagonal boron nitride (h-BNNS) with a specific surface area of 1 009.5 m2/g by boiling method. Then h-BNNS/CPAN fiber film was prepared by electrospinning method with h-BNNS and polyacrylonitrile (PAN) as the raw materials, and then Ag/h-BNNS/CPAN composite film was prepared by vacuum impregnation of silver salt. The morphology, elemental composition, microstructure and photoelectricity characteristics of the composite film were characterized.The results showed that the structure of h-BNNS was not changed after the introduction of Ag NPS, and it was uniformly distributed on the h-BNNS/CPAN composite fiber membrane.The effect of synthesis conditions on the properties of the composite was determined by the reduction of p-nitrophenol (4-NP) to p-hydroxyaniline (4-AP). It was found that the photocatalytic effect of Ag nanoparticles (Ag NPs) was the best when the calcination temperature was 220 ℃ and the content of h-BNNS was 25%. The apparent rate of photoreduction of 4-NP with the catalyst is 0.326 s-1.The photocatalytic reduction performance of Ag/h-BNNS/CPAN composite film was further investigated using CO2 reduction model reaction. The results showed that the photocatalytic activity of Ag/h-BNNS/CPAN composite film was directly proportional to the content of Ag NPs. When the Ag NPs content was 2.0%, the photocatalytic activity of Ag/h-BNNS/CPAN composite film was directly proportional to that of Ag NPs. The yield of CO2 to CO was 181.4 μmol/g after photocatalysis for 2 h.Combined with the photoelectric characteristics of Ag/h-BNNS/CPAN composite fiber film to analyze its photocatalytic performance, the mechanism of photocatalytic CO2 reduction reaction of the composite membrane can be explored, indicating that the synergistic interaction between Ag NPs and h-BNNS/CPAN composite fiber film in the photocatalytic reaction process can achieve high CO2 conversion.This study provides an effective way for the design and synthesis of highly dispersed nano-metal photocatalyst carriers.