Abstarct: Vorskharan karst springs with average discharge of 1.4 m^3/s is one of the most important springs is in the country of Firoozkooh. This spring is located in the village of Vorskharan in the southwest of the Firoozkooh country. This spring is located in the eastern edge of the Garabagh syncline And it has appeared as a result of the operation of one of the branches of the Moshafasham fault that cuts the Garadagh syncline. The spring of aquifer consists of Mesozoic and Cenozoic rock units. In order to evaluate the hydrogeological and hydrochemical characteristics of the spring, the physical and chemical properties of spring water have been measured for 18 months. Studies have shown that the coefficient of variation in physical and chemical properties is relatively small. In addition, the landing curve has a slope and its discharge coefficient is about 0.003 The decrease of the coefficient of discharge variation, hydraulic conduction, the main ions and the single-slope of the subsurface curve due to the drawn aquifer shape and the long-term presence of snow in the basin of the spring. The presence of a number of sinkholes and blocked pits in the basin of spring indicates that the basic system of flow is not in the diffuse. Due to the relatively high discharge of the spring and the reasons stated above, it can be said that the flow system in the spring basin is of the diffuse–conduit. In this research, the catchment area of spring was drawn as a preliminary. According to the specified area, an catchment area of about 47 square kilometers were estimated for Vorskharan spring. Average annual precipitation for the specified area equals 722 mm, assessed using elevation – precipitation graph of the studied area. Also according to field observations and percentage of soil cover, development of solutional spaces, dissolution and other karst morphological features, percent annual recharge in the study area calculated that is equal to %55. Considering the precipitation volume, percent of annually recharge, the annually recharge volume in catchment area was 19 million cubic meters obtained. In addition, the annual discharge volume via annually hydrograph of spring was calculated that is equal to 21 million cubic meters. Annual recharge and discharge volumes were compared that relative error is of about 2.5 percent. This negligible error between annually recharge and discharge volume in the basin represents calculated the catchment area had appropriate precision.