investigation monetary policy specially in oil countries is very important because oil exporter wiil be faced many challenge. i this paper try to take a look to the uncertainity and monetary policy in iran. i use macroeconometric modeling framework to investigate the design of monetary policy when the central bank faces uncertainty about the relationship betwwen inflation and unemployment. also on the base of a loss function for central bank ; a optimal monetary policy has been cocluded. i find that the performance of the monetary policy is closely matched by a simple operational rule that focuses solely on stabilizing inflation. Furthermore, this stabilization rule is remarkably robust to uncertainty about the model parameters and to various assumptions regarding the nature and incidence of the innovations. However, the characteristics of optimal policy are very sensitive to the specification of the money expantion mechanism, thereby highlighting the importance of additional research regarding the structure of labor markets and inflation.