In this study, tectonic features and subsurface structures in the Thrace Basin located in the European part of Turkey were investigated by using gravity, magnetic, well and seismic reflection data in integration. The Thrace Basin is filled by the Tertiary clastic sediments with maximum thickness of about 7.5 km and the basin is very prolific for natural gas potential. In this respect, firstly gravity anomaly map was evaluated and then 3 km upward continued map was prepared. Analytic Signal was applied to the upward continued map. The gravity anomalies were modelled in three and two dimensional methods with the seismic and borehole data control. When the results are compared to the regional geology in the basin, it is determined that the deepest section of the basin is 7.5 km to the north of Hamidiye and around Luleburgaz. In general, average sedimentary thickness of the basin is about 4.5 km.