The power system security accident cause model from the coupling perspective is studied, and the coupling relationship among power system risk factors is analyzed from the point of view of a single factor, two factors, and multiple factors. The N-K model is used to measure the risk coupling degree of 503 power system accidents from 2014 to 2022. The findings indicated that as the number of participating factors in the coupling process increased, the degree of coupling increased. Among the factors, human and equipment factors played a prominent role in the coupling of power system accident risks, resulting in higher levels of risk. Consequently, it is crucial to strengthen the management of key factors during the coupling of power system accident risks to prevent multi-factor coupling in vulnerable areas of the system.