At present， the Bohai Sea working area has achieved full coverage of 3D acquisition， but the construction time span of different working areas is large. There are a variety of acquisition methods， so different working areas have great differences in acquisition direction， offset range， amplitude difference， frequency characteristics， signaltonoise ratio and other aspects， which brings arduous challenges to buried hill imaging in the overlapping area of multiworking areas. In order to improve the imaging quality of buried hill structural area， this paper focuses on three aspects： fine key processing technology， fine splicing technology and high precision 3D prestack depth migration. Through the actual data verification， the imaging effect of the proposed method on buried hill of old data in the overlapping area of multiple working areas in Bohai Sea is significantly improved， which better verifies the effectiveness of the proposed method.