This research is a study of the runoff and sediment in a basin scale using the SWAT model. The Mae Chaem river basin is selected as the study site. The objective is to find the suitable parameters of the SWAT model for the study basin and to assess amount of runoff and sediment in the basin under the change of land use scenarios, the reduction of the forest area to agricultural area. The result shows that the SWAT model provides a good result for runoff and sediment amount estimation during the calibration period. During the model validation period, the model indicates fair result. From the land use change scenarios analysis, it can be found that the amount of runoff is increased by 10% 15% 19% 23% and sediment is increased by 21% 36% 46% 55% when forest area is reduced to be the agricultural land instead in the amount of 10% 15% 20% and 25%, respectively. The result of this research confirms that the SWAT model is reliable and can be used effectively as an analysis tool under various future basin change conditions.