Seismic refraction surveys were conducted in Leylanchay Dam near Malekan, Eastern Azarbayjan province to determine depths of the alluvium in dam site. Refraction seismic data collected from 4 location in dam site and interpreted with four methods of interpretation, include: Intercept-time method, Raytracing method, Generalized reciprocal method and Refraction Tomography. Four layers include saturated alluvial, unsaturated alluvial, saturated shale and dolomite were detected in seismic profiles. Thickness of alluvium ranged from 4 to 24 meter. Results compared with boreholes and geologic sections and good results achieved. Also this results indicated that Intercept-time method have a weak result in complicate subsurface models, however this method with Ray tracing method can prepare well initial models for other raytacing methods such as tomography. GRM could finely illustrate the lateral changes in layers velocity and tomography also prepared high quality model of depth and velocity