1. A seismic imaging method implemented by a program executed on a computing apparatus, for obtaining imaging data of a subsurface structure through waveform inversion using a macro-velocity model as an initial value, wherein the macro-velocity model which is used as the initial value for the waveform inversion is calculated by: calculating a velocity difference function which is a difference between a real velocity and an initial velocity model, wherein the velocity difference function is a ratio of measured seismic scattered energy and modeled scattered energy based on the initial velocity model; and calculating the macro-velocity model by updating the initial velocity model with the velocity difference function, wherein the calculating of the velocity difference function comprises: approximating measured seismic signals from a plurality of receivers to a sum of scattered waves to calculate the measured seismic scattered energy; calculating energy of pseudo-scattered signals from a simple velocity model; calculating a relative velocity anomalies ratio which is a ratio of a value of the measured seismic scattered energy and a value of the energy of pseudo-scattered signals; calculating the velocity difference function using a relationship between the relative velocity anomalies ratio and the velocity difference function; obtaining the imaging data of the subsurface structure based on the macro-velocity model using a subsurface imaging unit; and recording, storing, or fixing the imaging data and/or subsurface velocity data in a computer-readable storage media.