In radio frequency simulation system (RFSS), target simulation is confined to the limit of field viewing angles; gradient inertial coordinate frame (GICF) is effective on the problem. According to the engineering problem of GICF in RFSS, the essence of this problem is discussed, and then the related methods of coordinate transform are analyzed. Finally, the corresponding target simulation enrichment method is proposed. The simulation results indicate that the method can keep the target information of terminal-guided radar unchanged; extend the range and improve the precision of radio target simulation; and enhance the attitude simulation performance.