Abstract: Gate-oxide degradation is considered as a critical reliability issue for SiC MOSFETs, for example the important bias-temperature instability phenomenon. The recovery phenomenon is obvious because of the abovementioned instability after the stress is withdrawn, the fast and accurate monitoring method in reliability test is therefore of great significance. In this paper, a new method for the gate oxide degradation monitoring using the threshold voltage induced by the body effect (written as V_TH(body)) was proposed and experimentally verified. A theoretical model was firstly established to describe the relationship between V_TH(body) and gate-oxide degradation. Then the method to obtain the V_TH(body) from the curve of relationship between the body-diode voltage and the gate voltage in the switching process was proposed, and the influence of experimental parameters was studied in detail. Furthermore, the function of V_TH(body) were experimentally verified by a high-temperature gate bias (HTGB) test and compared with that of the threshold voltage V_TH. The result shows that this proposed method can fast and accurate realize gate oxide degradation monitoring under non-constant temperature environment.