N-Succinyl chitosan (NSC) with various degrees of deacetylation (DD 6-94%) and substitution (DS 0.14-0.79) were successfully prepared from N-acetylchitosans in varying reaction time. Infrared spectroscopy (IR), H-1 NMR and gel-permeation chromatographic (GPC) techniques were used to characterize their molecular structures. The moisture-absorption (R-a) and -retention (R-h) abilities of NSC are closely related to the DD and DS values. Under conditions of high relative humidity, the maximum R-a and R-h were obtained at DD values of about 50%, and when the DD value deviated from 50%, R-a and R-h decreased. Under dry conditions, when the DD value was 50%, the R-h was the lowest. The NSC with DS 0.65 to 0.79 exhibited better R-h than that of HA, and has the potential to prepare HA-like substances in pharmaceutical and cosmetics industries.