Abstract:One to 2-year-old seedlings of two lychee (Litchi chinensis Sonn.) cultivars (droughtsensitive Chenzi and drought-resistant Dongliu 1) were planted in pots by moisture stress and normal watering to determine the relative water content (RWC) and the H+-ATPase activities in leaves. The effects of water stress on (specific) activity of cytoplasmic, ionically and covalently wall-bound H+-ATPase in leaves were studied. The results showed that RWC in leaves decreased with increasing water stress, but such decrease was 1ess in drought-resistant cultivar than in drought-sensitive one． The activities of cytoplasmic， covalently wal1-bound and ionically wall-bound H+-ATPase were 81.8O％-83.15％-11.48％-12.3O％ and 5.37％-5.9O％ of the total H+-ATPase activity, respectively．No significant difference was observed between two cultivars． Under water stress, the (specific1) activities of cytoplasmic, ionically wall-bound and covalently wall-bound H+-ATPase in leaves increased． The extent of increase was higher in drought-resistant cultivar than in drought-sensitive one．