A new two dimensional joint inversion algorithm for Seismic refraction, Radio-magnetotelluric and DC Resistivity data was developed. We used synthetic data to show advantage of the algorithm. The developed joint inversion algorithm found resistivity and velocity model better than the individual inversion of each data set if one compare with the real models. We also tested the algorithm with the field data collected in the Bafra basin to image the saltwater intrusion at this area. The field data inversion is also showed that the joint inversion recovered the resistivity and velocity model better than the individual inversion of each data set.