It is important to prediction of precipitation changes to know how much it will change in the future and to consider the necessary measures to mitigate the adverse effects of climate change. Therefore, in this study, precipitation changes in the west of the Iran were predicted. For this purpose, the data of CanESM2 model were used under three scenarios of RCP2.6, RCP4.5 and RCP8.5 using the SDSM downscaling model and was investigated the changes of precipitation in the period (2021-2050) compared to the basic period (1989-2018). The MAE, MSE, RMSE and R2 indicators were also used to ensure the calibrasion and validation of the SDSM model. The results indicate the appropriate accuracy of this model in the study area. The results of a monthly survey of precipitation at the study station showed that precipitation will increase during the period (2021-2050) in most areas from October to December, and in some areas in addition to January to April. Based on this, it is expected that the amount of precipitation in the next period compared to the basic period will increase between 0.05 and 15% on average in the study area. Most of the changes are related to the northern and eastern areas of the study area and the least changes are related to the southern areas of the study area. Also, the highest and lowest changes are predicted based on RCP8.5 and RCP2.6 scenarios. Due to the complexity of the precipitation process, there are always uncertainties in the field of precipitation forecasting, and it is necessary to use the results of the models in this field with caution and to increase the accuracy of forecasting from different GCM models and microscale methods. Different used. Also, considering the increase and intensity of rainfall and mountainousness of the study area, the necessary strategies to deal with floods and its management should be considered.