A drug carrier is provided with a structure of a lipid shell enclosing aqueous micelles. The lipid shell includes lipid and emulsifier, in which the emulsifier encloses the lipid. The components of the aqueous micelles are phospholipids and amphiphilic chitosan, and the aqueous micelles enclose an aqueous solution containing a drug. Furthermore, the method of preparing the drug carrier is also provided. Therefore, with the pharmaceutical advantages of lipid-based nanoparticle included low drug leakage and the ability of to overcome the multiple drug resistance, this new formulation were further incorporated with the chitosan and featured with high payload efficiency. The features could enhance intracellular concentration of anti-cancer drug and oral bioavailability.