The invention discloses a modeling method of a well-seismic merging velocity model based on a tectonic level. The modeling method comprises the steps of: S1, inputting a level depth, a well logging velocity and a prior velocity in a priori velocity model; S2, performing abnormal value elimination and smoothing processing on the well logging velocity; S3, counting a ratio of the well logging velocity to the prior velocity on a large scale, and correcting the well logging velocity; S4, selecting a reference well, projecting the well logging velocities of other wells to the reference well along the level to form a velocity curve with uniform depth; S5, calculating an interpolation weight of each well based on the velocity curve after depth unification; S6, subjecting an interpolation point toweighted interpolation to obtain a preliminary interpolation velocity of the point; S7, projecting the interpolation velocity from the reference well to the interpolation point to obtain an interpolation result; S8, subjecting interpolation points to weighted interpolation one by one, and constructing a well velocity speed by means of interpolation results of the interpolation points; S9, and merging the well velocity model with the prior velocity model so as to form a top-down well-seismic merging velocity model.