The storage, transportation and disposal of pressurized water reactor (PWR) spent fuel is an important issue in nuclear industry for safe and extended nuclear power plant operation. However, since wet-storage facilities almost reach to their capacity, dry-storage method, especially using a Multi Purpose Canister (MPC), has been highlighted because it gives better economic and safety point of view. In this study, an advanced design of MPC was proposed through an increase in storage capacity from 26 to 37 PWR fuel assemblies per MPC. Thermal analysis was also carried out by FLUENT 6 code to confirm the temperature criteria of the MPC. From the results, conceptual design of 37 PWR fuel assemblies can reduce the mass per fuel assembly ratio about 19 % compared to the 26 assemblies, and maximum temperature developed at the center of fuel assemblies shows within the range of design criteria. Based on the analysis, it is considered that the advanced MPC design well conforms to the safety requirement and it gives rise to economical gain because of reduction in mass per fuel assembly ratio.