The work aims to investigate the effects of polylactic acid (PLA) and polyethylene (PE) packaging bags on preservation quality of broccoli. The barrier properties of PLA and PE films commercially available were tested via oxygen permeability instrument and water vapor permeability instrument. The PLA and PE bags were used to package the broccoli. The effect of such bags on the preservation effects of broccoli respectively at room temperature and under cold storage condition was investigated by colorimeter and headspace analyzer. The results showed that the water vapor permeability coefficient and oxygen permeability coefficient of the PLA film were respectively 1.241×10−13 g•cm/(cm2•s•Pa) and 5.07×10−10 mL•cm/(m2•s•Pa); those of the PE film were respectively 1.125×10−14 g•cm/(cm2•s•Pa) and 2.87×10−10 mL•cm/(m2•s•Pa). With the extended storage period, the color of broccoli changed from green to red, and from blue to yellow. The lightness turned from black to white. The O2 concentration in the bags initially decreased and then increased, while the CO2 concentration was on the contrary. The water vapor permeability and oxygen permeability of PLA film are better than PE film. The PLA bag can inhibit the respiration of broccoli stored under cold storage conditions more efficiently than PE bag.