The invention provides a fidelity amplitude
gaussian beam pre-stack depth migration method under double complex conditions. The specific realizing process comprises the following steps: firstly, according to the initial width of a selected
gaussian beam, a
single shot record is divided into a series of overlaid areas through a
gaussian window, and the center of each area is a beam center; secondly, through considering the slant stack of
earth surface elevation, the shot
record corresponding to a beam center is divided into plane
waves in different directions; thirdly, the gaussian beams are respectively test-fired from a
vibration source and the beam centers, and the
travel time and amplitude information in the effective range of each
gaussian beam are calculated; fourthly, according to an deduced fidelity amplitude imaging formula, the imaging value corresponding to one beam center is calculated by utilizing calculated
travel time, amplitude, and the local inclination angle information of
earth surface; and fifthly, the operation of the step three and step four are repeated to obtain the imaging result of the
single shot, all
single shot imaging results are overlaid to obtain the final offset result. With the invention, the energy strength of a deep layer (the position indicated by an arrow) is effectively strengthened, and the light layer
noise (the position indicated by the frame) is suppressed, so that the imaging accuracy of near
earth surface is improved.