Abstract: In conventional sparse 3D seismic acquisition, the large line interval leads to poor seismic coverage density. The theoretical analysis and seismic acquisition examples demonstrate that when the shooting distance and the trace?to?trace interval basically meet the spatial sampling theorem, we should pay full attention to the spatial sampling density in direction of shooting line spacing and geophone line spacing. Reducing such two spacings to improve the coverage density can expand 3D space bandwidth and achieve the aim of enhancing the prestack migration imaging accuracy, allowing the prestack migration trace gathers and the signal?to?noise ratio of imaging data to be significantly improved