In any analysis of macroeconomic problems and economic policies, an investigation of import and export demand function occupies a significant and crucial role in effectiveness of trade policies.This paper is aimed to assess the role of total factor productivity (TFP) on nonoil exports and imports for the period 1959-2003.The results indicate that 1- the relative price index - that is the ratio of import goods to export goods in domestic prices - and total factor productivity has a adverse and considerable impact on import demands while domestic national product (GDP) (without taking oil production into account), and oil revenues have a positive impact on import demands. 2- total factor productivity, real exchange rate and the level of world import positively affects nonoil exports. In addition, we discuses various economic shocks and their immediate effects on nonoil exports and imports as well a s on different determent of import demand and export supply using the impulse response and variance decomposition analysis.