Sea transportation is the base of trading and plays a major role in supplying commodity chain. In this chain, Ports as the stimulants of economic activities of countries and connecting ring between land and sea transportation ensure the steady flow of goods and services and provide traders and owners with the economical way to exchange goods. Khorramshahr is one of the most important ports in Iran and is located in the northwest of Persian Gulf and southwestern Iran (Shalamcheh land border) neighboring southeastern Iraq and is located at the confluence of the Arvand and Karoon rivers in Khuzestan province. This study examined the effects of changes in fuel prices on sea freight in Khorramshahr port in order to determine the effectiveness level of each factor in changes of transportation costs .This study is based on annual data time series 1996 to 2012. The research results show that the ship's fuel price is directly proportional to the sea freight, the demand for sea transportation varies inversely with the increase in fuel prices are, fuel consumption rate is directly proportional to weight of transported goods (ton/mile) and increasing in the number of freighters varies inversely with sea freight.