The high resolution seismic profiles displays that a growth fault bend fold occurs in the western depression of the Liaohe basin. This paper presents a detailed structural interpretation to seismic section, and then describes the deformed geometry related to the pre growth strata, the growth strata and the post growth strata on both limbs of the fold. The computer geometric simulation, based on the model of fault bend fold, was utilized to stimulate the geometry of the growth fold in south and north segments of western depression. These structural features were subsequently extracted and compared with the actual seismic reflection section. Our research suggests that an overthrust formed during the early Cenozoic also appears in Taian Dawa fault which is the northern section of Bohai breach in Tanlu fault zone. The event of structure mainly took place at the depositional stage between the lower three member of Shahejie and the former Guantao formations (E2s3L~N1g), with a thrusting rate of 0.116 mm/a.