N,O-Carboxymethyl chitosan(N,O-CMCh) of biocompatible derivatives of chitosan was prepared by chemical reaction with Mono-chloroacetic acid and glyoxylic acid on low molecular weight water soluble chitosan(LMWSC) of C6 position -OH and C2 positon -NH2 group to apply as cationic drug carrier. The substitution of carboxymethyl groups on 6-O and 2-N can be determined by 1H-NMR. Degree of substitution (DS) and degree of deacetylation(DDA) of N,O-CMCh were 96%, 98%(6-O) and 45%(2-N) respectively. DS of the C6 -OH group had higher than C2 -NH2.