Abstract: Three-D high-density seismic techniques evolving from 3D seismic techniques and 3D high-precision seismic techniques are still not sufficient for hydrocarbon exploration and development in complicated surface, tectonic, and reservoir conditions.To achieve high-precision imaging in complicated surface and subsurface conditions, we present a new idea of "ultra-high-density seismic techniques" based on the development of high-density seismic techniques, computer technology, and geophysical equipment.Field experiments with small group intervals and forward modeling with small grids show improved near-surface velocity modeling, static correction, and imaging of deep-seated steeply dipping fractures by ultra-high-density seismic acquisition.The strategy of "variable group interval+interpolation" is combined with supporting techniques relevant to instruments, storage, and computation to address the issues of acquisition instruments, mass data, and economic feasibility.Nodal seismograph with the level of 10×10⁴ channels and mass data storage and computation are the foundation of utilizing ultra-high-density seismic techniques; key techniques include high-density acquisition with "small trace distance, small bin, wide azimuth, wide band, high coverage, high shot and trace density", prestack reverse-time depth migration with a "small smooth surface", and compressed sensing or 5D interpolation.To further improve the precision of imaging, seismic acquisition with the shot channel density over 200×10⁴ should be developed; associated equipment and techniques to be developed include large-scale single-point nodal seismograph, devices for mass data storage and computation, and interpolation with variable group interval.Field seismic acquisition should also be propelled.