The Alsafarqieh watershed is located on the western slopes of the coastal mountain range, Its area is 132.58 km2, It forms a part of the Alros river basin, The river starts at a height of 1200 m, A group of tributaries meet and form the Alros River, which flows into the Mediterranean Sea. Salaheddin Dam was constructed to store 10 MCM on the riverbed at the intersection of the Qurdaha River with the Shehada River. The study aims to determine the rainfall- runoff relationship in The Alsafarqieh watershed. The solution depends on the statistical analysis of precipitation and runoff data. Then the study found the mean annual precipitation is 159.6 MCM/year, and the mean annual flow into the Salaheddin lake was 9.4 MCM during the study period (2010-2012), so the runoff coefficient is 0.06. This indicates a significant water loss. A mathematical equation to predict the runoff quantities depending on the values of precipitation, has been concluded. This is important to study water projects for water storage and flood prevention.