With the oil/gas development going deep, the focal points of the depleted oilfield's oil/gas exploration in East of China has been shifted from structural exploration to structure-lithologic or lithologic exploration. Tapping the latent power of depleted field presented a higher demand for seismic personnel. The popularization of secondary 3-D seismic exploration has solved the “bottle neck” problem of exploration & development, the improvement of data quality established a good foundation for increasing reserve and production in east depleted field. In this paper, we took mainly the secondary 3-D seismic explorations in Jidong oilfield and Huabei oilfield as an example, and analyzed the secondary 3-D seismic exploration technology, among which the Gaoshangpu and Liuzan areas of Jidong oilfield and the Liuxi Dawangzhuang area of Huabei oilfield are the focus points analyzed. By strengthening the geometry design, optimizing in situ and aided by fine near-surface structural survey ( surveying aquifer and lithology), shooting in aquifer and better lithology and operating during low environmental noises, the quality of acquired2 data in secondary 3-D seismic exploration has been greatly improved.