With the increasing application of insulated gate bipolar transistors (IGBTs) in power electronic equipment, its long-term reliable operation attracts widespread attention. The existing 2-dimensional (2-D) safe operating area (SOA) only describes the capability of brand-new devices to withstand electrical stress with a specific ambient temperature. The long-term operation is not considered, and the electrical-thermal coupling analysis is not convenient when approaching the practical mission. In this paper, a 3-D SOA model including the case temperature dimension is illustrated, and a long-term SOA model considering aging impact is proposed. By aging evaluation, the cumulative damage is calculated to evaluate the health condition, and the thermal impedance is selected as the aging-sensitive parameter impacting SOA constraints. A case study is adopted and a simulation is constructed to reveal the shrinkage of SOA with the long-term operation, emphasizing the necessity of considering IGBT safety throughout the whole lifespan in converter design.