This study focuses on the stress state of silicon carbide (SiC) power devices after the end of dynamic gate bias stress (DGS), and the influence mechanism of different pretreatments on the device threshold voltage (Vth) shift. Through a combination of experimental design and theoretical analysis, the impact of the instantaneous electric field distribution and charge trapping/release behavior at the end of dynamic gate bias on subsequent Vth stability was systematically explored. Research results show that the stress state (positive voltage/negative voltage) at the end of dynamic gate bias and whether pretreatment is performed will significantly affect the Vth shift of SiC devices under dynamic operating conditions. This research provides important theoretical basis and experimental guidance for the stability design and reliability improvement of SiC power devices.