Since the middle of 1950's when sea transportation service by container ship was established, containerization has been rapidly spread over the world with realization of intermodalism, and becomes an index of economy growth of a country. Our country has established Pusan Container Terminal at Pusan harbour in 1978 in step with worldwide trend of containerization, and is constructing New Container Terminal at Pusan outharbour which will be completed in 1990. This paper aims to make a quantitative analysis of the Pusan Container Terminal system through the computer simulation, especially focusing on its subsystems such as ship stevedoring system, storage system and transfer system. First, the capacity of various subsystems are evaluated and it is checked whether the current operation is being performed effectively through the computer simulation. Secondly, the suggestion is presented to improve the operation by considering the throughput that Pusan Container Terminal will have to accept until 1990, when New Container Terminal will be completed. The results are as follows ; 1) As the inefficiency is due to the imbalance between various subsystems at Pusan Container Terminal on the basis of about 1.2 million TEU of container traffic, transfer equipment level must be up to 33% for transfer crane, and free period must be reduced into 4/5 days for export/import. 2) On the basis of about 1.4 million TEU of container traffic, transfer equipment level must be up to 12% for gantry crane, 11% for straddle carrier and 66% for transfer crane, and free period must be reduced into 3/4 days for export/import. 3) On the basis of about 1.7 million TEU of container traffic, transfer equipment level must be up to 25% for gantry crane, 28% for straddle carrier and 100% for transfer crane, and free period must be reduced into 3/4 days for export/import. 4) On the basis of about 2 million TEU of container traffic, transfer equipment level must be up to 25% for gantry crane, 30% for straddle carrier and 110% for transfer crane, and free period must be reduced into 2/3 days for export/import, and it is necessary to enlarge storage yard.