The effect of polymer (Carboxymethelcellulose ) treatment of different soils of 16 Tishreen lake basin on the Mean Diameter of Weighted Granulares by using 5 concentrations of polymer (0-5-10-20-25 )mg/L , and Relative Flocculation Index was studied . The rate of runoff and the amount soil eroded were studied as well by exposing 3 soils treated with different concentrations of polymer ( 0-10-20 Kg/ha ) to rainfall intensity (30 mm/ hour) by using simulated rainfall . The results showed significant increase of soils MWD treated with polymer compared to the control , and decrease of slaking values and light absorption which lead to increase Relative Flocculation Index . The runoffrate of soils (2 ,3, 4 )treated with polymer decreased by 18% and 31.8% , 16.7% and 50% , and by 53.3% and 46.7% , respectively, compared to the control. The amount of lossingsoil was diminished by treatment with polymer ( 10-20 Kg/ha) by 18.3% and 40.8% , 25.9% and 39.2% and by 52% and 53.4% in soils 2 , 3 and 4 , respectively .