In order to study the effect of bagging on outward and inner quality of navel orange, we took Citrus.sinensis cv.Bionanza Navel, C.sinensis cv.Newhall Navel and C. sinensis cv.Washington as the materials in Xinnin and Anhua in 2001.The result shows that bagging can greatly improve outward quality of navel and promote fruit increase as well,especially in arought condition. Bagging can decrease soluble solid substance and total sugar, but there is little difference.The difference between the effects of monolayer black bag and double deck black bag is not so remar...