Taking strawberry‘Hongyan’ as test material，this study compared the effects of PO and PE film covering materials on greenhouse environment conditions，including temperature，humidity，illumination and strawberry yield and quality in over-winter sunlight greenhouse. The results showed that using PO film the average temperature of greenhouse was about 1 ℃ higher than that using PE film. The heat preservation was better，humidity was suitable，and lightening effect was also good in greenhouse using PO film. Besides，the strawberry yield increased by 23.27%，rotten fruit percentage was reduced ，contents of soluble solids and VC，sugar/acid ratio were all increased obviously，and the strawberry tasted even better.