Abstract: It is believed that thick Mesozoic-Paleozoic marine strata are widely distributed in the central uplift region of the South Yellow Sea Basin. There is enormous hydrocarbon potential.However,the geophysical and geological conditionsare extremely complicated in this region. The quality of seismic profiles is low,and the S/N of seismic data very high. Upon seismic wave field numerical simulation, it is discovered that the low quality of seismic sections comes from various reasons, such as the strong shielding layer in shallow part, weak reflectance of the Mesozoic-Paleozoic strata, and intense multiple energy.To resolve the problems,the authors made a series of researches to improve the key techniques for seismic data processing aiming at the Mesozoic-Paleozoic. Several key technique series are proved effective, which include combined multiple suppression,noise attenuation in disparate domain,improving S/N. The S/N of the Mesozoic-Paleozoic seismic data is effectively improved, and the seismic imaging quality becomes better.