The invention discloses a method and device for calculating a full-crustal extension coefficient based on subcrustal flow and
magma invasion
recovery, and the method comprises the steps: obtaining geological comprehensive data, such as a
seabed seismic survey line and deep reflection multichannel seismic section data, of a target region, carrying out the stratigraphic division according to the geological comprehensive data, constructing a time-
depth conversion formula through the drilling and
logging data, and carrying out the calculation of the full-crustal extension coefficient. And converting the
time profile data into depth domain data. And establishing an
earth crust structure model in combination with a stratigraphic division result and related data, calculating a
gravity anomaly curve through forward modeling and correcting the model until a preset condition is met so as to obtain density structure distribution of each part of the profile, and extracting the thickness of the
earth crust high-density body. And then, according to the abnormal settlement after
cracking, the
earth crust loss amount is extracted, the current earth crust thickness is recalculated by removing the earth crust high-density body thickness and supplementing the earth crust loss thickness, the corrected earth crust thickness is obtained, and finally the whole earth crust extension coefficient is calculated. According to the method, the influence of bringing-in and taking-out of crustal substances is eliminated, and the accuracy of evaluating the crustal extension change rule is greatly improved.