Applied for Drug Delivery System, polymer drug was prepared with chitosan and phthalylsulfathiazole. In spite of various application of chitin derivatives, commercial use of chitin has been limited due to highly resistance to chemicals and the absense of proper solvents. In this study, Chitosan were prepared from chitin which were deacetylated under various condition. The synthetic procedures of polymer drug were performed by acid chloride methods. The antibiotic activities of polymer drug exhibited growth-inhibitory activity against Staphylococcus aureus, Staphylococcus epidermidis, E. coli, Salmonella typhimurium, Klebsiella pneumoniae at the concentration of 471-514 $mu$g/ml in general. Comparatively, Polymer drug exhibited broad antibacterial activity on MICs 897-1280 $mu$g/ml against Gram-positive and Gram-negative bacteria including Staphylococcus aureus, Staphylococcus epidermidis and E. coli.