Abstarct: Abstract The studied area is located 32 km northwest of Shahrood city on the road and northwest of Mojn city. In order to identify the main flow paths in the karsts of the region, the formations of the identification region, the laxyering process and the structures formed in them were investigated. In the north of the study area, Shamshak formation with a set of sandstone, shale, siltstone with interlaxyers of coal, with laxyering trend (east-west) and laxyering slope (south), hydrogeologically, with an impermeable and impervious set as an underground dam. It prevents the current from passing to the north. In the south of the Lar formation, the basalt intrusive mass has controlled the flow towards the east and has formed a separate aquifer; where its underground water discharge point is the black springs of the valley and Palizo. In the western part, due to tectonic changes and topographic slope change, it was formed due to the strike-slip fault in the northwest-southeast direction of Pi-Hesar spring. baxsed on the field visits, the watershed was considered for them; In order to obtain the error rate of these basins, we first measured the output flow of these springs in a period of the water year and the volume of their discharge in one year. By obtaining the infiltration coefficient (baxsed on the expert's opinion), the amount of precipitation (baxsed on the height-precipitation diagram and calculating the average rainfall in the basins) and the area of the catchment area determined for the springs, we obtained the amount of nutrition. With a minor error of 1%, the determined catchment area is correct. Since the structures formed upstream of Derkhanio spring are not able to supply the outflow water resulting from it. The western part of Mojn city was investigated. baxsed on geoelectrical studies, investigation of the drilling log of dug drinking wells, analysis of the output flow of drinking wells and field visits, it was determined that the western area of Mojn city is a large depression with a gentle slope towards the east. from which the Majen aquifer is supplied; And a part of the underground water flow of this aquifer shows itself in the form of springs due to fractures and sediments formed. In general, the main flow of underground water in the direction of laxyering, the process of fractures, the axis of the folds is moving towards the east with the influence of the absolute and local baxse level.