The effect of carbon and nitrogen sources on the accumulation of Poly-beta-Hydroxybutyrate (PHB) by purple non-sulfur photosynthetic bacteria (PNSB)was investigated. The results showed that ammonia nitrogen and organic nitrogen could benefit the PNSB accumulating PHB; under certain ratio of carbon and nitrogen low carbon concentration can accumulate more PHB, but high carbon concentration is better for PNSB accumulating PHB with the growth of PNSB. As to different substrates, butyrate is the best for accumulating of PHB, but acetate is better and propionate is the poorest. Mixed substrate with butyrate as the main content are better than single substrate; carbon dioxide have certain effect on the PNSB accumulating PHB, and high carbon dioxide concentration can improve PHB content when using acetate or butyrate as substrate.