Low molecular and water soluble chitosan (LMWSC) nanoparticles were prepared by dialysis method as modify the chitosan with hydrophobic and hydrophilic group and investigated the potential as a drug carrier. The nanoparticle prepared in this study would be used to both of intravenous injection and oral administration of hydrophobic drugs due to their adequate size for administration. We measured critical micelle concentration (CMC), photon correlation spectroscopy (PCS), and AFM to investigate the character of the nanoparticles. From the results of surface morphology observed by AFM, spherical nanoparticles were identified and its size was 30~150 nm. At PCS measurement, the more increase the number of substitutive group, the more decrease the positive charge of nanoparticle surface. The CMC of nanoparticles are different according to the amount of hydrophobic group.