Precipitation variability and drought - wet forecasting are related to changes in signals of atmospheric - oceanic.Considering this, the most important goal this study is to investigate the relationship of stations rainfall in the West of Country and the Eastern Mediterranean Oscillation. Hatzaky and Flokas identified two cores using methods of correlation analysis and principal component analysis (PCA) on a monthly and seasonal time series which were situated between the East Mediterranean and Northeastern Atlantic and at 300 and 500 hPa levels that named as the eastern Mediterranean pattern (EMP).To identify the relationship between rainful in west of Iran and eastern meditrranean oscillation,the values of this index which are standardized have been studied and compared with normalized data of country,s west stations rainful,using pearson correlation analysis,linear and polynomial process. The study results show that ther is a negative correlation between the stations precipitation of the north of the under study region and the above mentioned oscillation,and ther is a strong positive correlation in southern stations,that most of them are meaningful at 0.05 level. Also, this study proves that stations precipitation in southern half of the under study region in positive phases increases from 5 to 41 mms and in negative phases decreases from 4 to 20 mms.But, contrary to southern half, in the northern half the rainful increases up to 8 mms in negative phases and precipitation decreases in posetive phases.