In recent years, shipping and ports industries are faced with enormous changes like globalization, market liberalization and borderless businesses. To cope with this competitive environment, a certain form of cooperation among ports is necessary to provide high quality of services and lower costs to establish their market power against shipping companies. The purpose of this study is to identify the motivation of the strategic alliances between ports and demonstrate the level of importance using Analytic Hierarchy Process(AHP). Among four motivations of the strategic alliances which are strategic motivation, economic motivation, operational motivation and marketing motivation, economic motivation is the most important factor for ports alliances than other factors. This is because economic motivation among strategic alliances allow ports in the same market to rationalize supply and demand, thus avoiding unnecessary over-supply and over-competition and also can reduce service costs by using comparative advantages of each partner which make costs cheaper.