Abstract: Under water stress, leaf RWC,ψW, Pn,soluble protein and chlorophyll contents in pomelo seedlings were decreased, the contents of MDA and free proline, SOD activity were increased, CAT activity increased at first, then decreased. And activity of APX, the contents of AsA and GSH were declined too. The activated oxygen decomposing capacity in the drought_resistant variety was higher than that in the drought_sensitive one. CPPU treatment increased leaf RWC,Pn, chlor ophyll,free proline,AsA,GSH contents, SOD,APX activities, and decreased the accumulation of MDA, therefore the drought resistance of pomelo seedlings was improved. These results indicated that CPPU treatment increased protective capacity against membrane lipid peroxidation, therefore resulted in the increase of drought resistance of pomelo seedlings.