Abstarct: In order to investigate subsurface geological structures, determination of resistive bed rock depth, investigation of lateral discontinuities (e.g. fractures) and local anomalies in Chooman dam site, electrical resistivity and refraction seismic data have been acquired, processed and interpreted. The aim of this research is the recognition of the subsurface structures by integration of the results of the two methods. In this study, refraction seismic method has been performed to determine the velocities of P and S waves in the subsurface. In addition, resistivity method using the Schlumberger and CRP electrode arrays has been carried out. The refraction seismic surveys have been carried out along 24 lines for recording P and S waves. Geoelectrical surveys include 400 sounding points performed using the Schlumberger array, and 100 measurements using CRP array. The resistivity results indicate that the resistivity method has been well capable of recognizing subsurface structures. In this research, the most important parameters of soil engineering in Chooman dam site are determined using refraction seismic method. For this, P and S waves have been recorded along 24 seismic lines. First, conventional pre-processing methods have been applied on the data, and travel time curves for each line have been drawn. Then, the data using generalized reciprocal method have been processed and interpreted. As a result, bed rock cross-sections have been obtained in which the bed rock depth variations between 3 to 12 meters have been demonstrated that implies the low thickness of alluvial sediments. After that, considering the velocities of P and S waves in the subsurface laxyers, geotechnical parameters such as compressibility modulus, bulk modulus, density gradient and stress ratio have been computed. baxsed on the results obtained from the velocities of P and S waves, no considerable anomaly has been recognized in the subsurface. Thus, the velocities of the waves in the faults existed in the dam site indicate low impact fractures implying relative compactness of the laxyers in the subsurface. Considering integration results of refraction and resistivity methods by GIS and the detection of a fault in central part of the study area, in which better quality data have been obtained, by controlling the fault, construction of the dam can be commenced in the area