Abstract: In order to study preservation effects of nano-composite materials to harvested Lentinus edodes, compared with unpacked ones, this article meaned to discuss the preservation effect of PLA composite films in which added different mass fractions of nanometer Ti O₂ ( the Ti O₂ fractions: 0%, 1%, 2% and 3%) to Lentinus edodes. Lentinus edodes ' physical and chemical indexes, as well as microbiological indicators, were measured every 4 days when storing at the temperature of ( 4 ± 1) ℃.The results demonstrated that polylactic acid nano-Ti O₂ composite film could better maintain the sensory quality, reduce respiration intensity and the loss of moisture, keep VCand reducing sugars contents of Lentinus edodes in storage period. The additive amount of nano-Ti O₂ was proportional to the preservation effect, and the preservation effect of polylactic acid with 3percent fraction of nanometer Ti O₂ to Lentinus edodes achieved the optimal effect.