During voltage sag, the Inverter-Interfaced Distributed Generation (IIDG) may suffer from overcurrent and disconnection, which affect the safe and stable operation of IIDG and the power system. Thus, a new IIDG control strategy considering different operation scenarios is proposed. First, by considering the phase voltage amplitude constraint, a positive sequence components-based voltage support method is established. This maximizes the voltage support capability. To fully use the inverter capacity and ensure its safety, a scenario classification method considering the severity of voltage sag and the active power of the IIDG is presented. Based on the current injection mode of each scenario and the control objectives, the reference currents are calculated to ensure voltage support and current limitation. By delivering the active power and negative sequence reactive power, both system stability and voltage imbalance are improved. Finally, a simulation model with IIDG is established based on Matlab/Simulink. The simulation results verify the effectiveness of the proposed strategy. This work is supported by National Natural Science Foundation of China (No. 61873159).