Poly (γ-glutamic acid) is a promising environmental friendly material with outstanding water solubility, biocompatibility and degradability. This review introduces the basal properties of γ-PGA, microbial production of γ-PGA, and the key factors affecting the yield of γ-PGA. Furthermore, the γ-PGA biosynthesis genes, γ-PGA synthetase complex, as well as the application prospects of γ-PGA in hydrogel and drug delivery, are also discussed.