Recently, amount of cargoes from main ports in Northeast Asia have rapidly increased and as well surplus port development in same region corresponded with the boom in external trade that resulted from successful export-oriented economics strategy by China, Japan and South Korea. To cope with this business circumstances, a certain form of port alliance is desperately needed to provide a suitable service to customer and establish their countervailing power against the shipping alliance. Nevertheless, Incheon seaport has not made a definite port alliance system with main ports in Northern China yet. Thus, the purpose of this study is to identify the key success factors to form a port alliance through examining previous studies. We have benchmarked previous studies which are related to main ports in global region and the questionnaire on customers of ports. By studying this, we are able to suggest a few strategies for forming successful port alliance to enhance Incheon port's capabilities in the long term plan. As a policy proposal, this study suggests Incheon port and main ports in Northern China should construct a logistics infrastructure through mutual investment and provide an incentive system when the ocean carrier makes port call to both ports.