The purpose of the present research is to identify, measure, and analyze the variable affecting the functions of rail and road transportation demand in hinterland transport network of Imam Khomeini Port using econometrics models and methods. So, the present research introduces appropriate and effective parameters which cause in elevation of cargo demand in road and rail transportation sectors of Imam Khomeini Port. Also, share of each variable is presented in the econometrics model and the demand elasticity is estimated. The data analysis is done using 2SLS method and monthly time series data from 2006 to2011. The results reveal that variable of oil and non-oil tonnage, the number of trucks, rail fleet tonnage, and the exchange rate, and population have positive effects; while other variables such as the number of wagons and inflation rate have negative effects on function of road transportation demand. Regarding the function of rail transportation demand, the variables of oil and non-oil tonnage, the number of wagons, rail fleet tonnage, exchange rate, and population have positive effects on function of rail transportation demand; while variable of number of trucks and inflation rate have negative effect.