Abstract: Petroleum exploration in deep to ultra-deep sea areas is important to offshore reserve and production increase in China. In view of complicated structural setting and high cost of production, offshore petroleum exploration and development with high quality and high efficiency rely on geophysical techniques to obtain high-graded reserves of scale and rapid production increase without drilling many wells. Thanks to theoretical innovation and technical application in the latest years, some medium- and large-sized fields, e.g. Lingshui 17-2, Lingshui 25-1, Baodao 21-1, Kaiping 11-4, and Kaiping 18-1, have been successfully discovered in deep to ultra-deep areas, the South China Sea. These discoveries have also advanced geophysical techniques. We use several case studies to illustrate the challenges and solutions in deep-sea prospecting. Varying layout acquisition is a proven solution to the complexities caused by submarine relief, sea water depth, and abrupt tectonic change to obtain high-quality seismic data. With respect to heterogeneous water velocity, multiple and ghost reflections, complex wave field induced by irregular sea bottom, and inaccurate velocity in a complex structural zone, such broadband techniques as high-precision velocity analysis through full waveform inversion and viscoelastic prestack depth migration are employed to improve the resolution and signal-to-noise ratio of seismic data. Rock physical experiments, seismic response analysis, and rock physical modeling are established to improve reservoir prediction, fluid detection, prestack source rock prediction, and non-bright spot gas identification. The article concludes with the thoughts and suggestions for the future technical development of abyssal petroleum geophysical exploration in China.