Based on the field observation and 2D seismic data interpretation, it is illustrated that the basal and intermediate detachment levels developed in NS-trending fold belt in the eastern part of Bengal Basin. The basal detachment level is developed below the whole fold belt, while the intermediate detachment level is only formed in the onshore and shelf area in the north-central segment of the fold belt. The analysis result shows that the intermediate detachment level is primarily controlled by the paleoslope, where mud-rich sediments were deposited, and detachment folds and faulted detachment folds are dominant in the north-central segment, while mud diapirs and mud volcanoes are dominant in the south segment. It is suggested that the differential décollement and structural style of the fold belt in eastern part of Bengal Basin is mainly controlled by the along-strike variations of tectonic shortening, sedimentary processes, and fluid overpressure.