Traditional silicon-based devices face limitations in high-power applications. However, due to its superior conduction properties, silicon carbide (SiC) materials have become a key focus in improving power device performance. This paper will analyze the performance of SiC NPT-IGBT devices under on-state characteristics. First, based on the physical structure of SiC NPT-IGBTs, a coordinate system is established. Using semiconductor physics knowledge and boundary conditions, a physical model for the on-state characteristics of SiC NPT-IGBTs is developed. The relationship between on-state voltage drop and conduction current is derived. Next, the influence of SiC NPT-IGBTs on the on-state voltage drop is studied. On-state voltage drop curves are plotted at different gate-emitter voltages, comparing calculated and simulated data. Finally, the effects of the quasi-neutral base region width and temperature on the on-state voltage drop are analyzed. The on-state voltage drop from the physical model is compared with simulation results to verify the rationality and accuracy of the developed SiC NPT-IGBT on-state model. This research provides a theoretical basis for the structural optimization and reliability improvement of SiC NPT-IGBT devices.