Both experimental and numerical modeling were carried out on EAST to study the radiative divertor plasma behavior with neon (Ne) seeding. Steady H-mode radiation feedback control regimes (frad~18-36%) were achieved by synergistic working of a divertor puff and supersonic molecular beam injection (SMBI) with Ne in the 2017 EAST campaign. Ne seeding effectively promoted divertor detachment while only causing a slight loss to the plasma stored energy in the experiment. To better understand the experimental result, analysis of the detachment process is introduced in this work. Two time slices namely before and after Ne seeding during the radiative divertor experiment in Shot #71021 were simulated by SOLPS-ITER code. The simulation results for upstream plasma agreed well with the experiment, and the divertor profile agreed well on the outer targets when ignoring drifts. Radiation distribution was also calculated by SOLPS-ITER, showing that there was a high radiation region near the X-point, which is consistent with the experimental measurements.