In power systems, MOSFET devices used in industrial chips exhibit more pronounced degradation when subjected to intense electromagnetic pulses than in conventional environments. Conventional reliability testing methods, which fail to simulate dynamic electromagnetic environments, are unable to accurately assess the changes in device performance under electromagnetic interference. In this study, we employed a transmission line pulse generator to apply pulse stress to N-type MOSFET devices, systematically investigating the degradation mechanisms by varying pulse features such as pulse cycle, amplitude, rise/fall times, and intervals. The results indicate that changes in the electrical properties of the devices are primarily influenced by two types of charged traps. Under the conditions of low pulse cycles, the current response of the devices may even exceed that prior to stress application. The study further analyzed the competitive mechanisms of these different traps during the device degradation process. Additionally, by varying the test temperature to mimic industrial application scenarios, we analyzed the degradation behavior of the devices under multi-physics conditions.