The invention provides a power transmission and transformation equipment state detection method. The method comprises the following steps of establishing an equipment maintenance risk model, an equipment failure risk model, an equipment detection risk model and a system operation risk model respectively; according to the equipment maintenance risk model, the equipment failure risk model, the equipment detection risk model and the system operation risk model, taking a minimum total system risk as a goal and establishing an equipment state detection strategy optimization model including an objective function and a constraint condition; and according to the equipment state detection strategy optimization model, acquiring above parameters. In the invention, equipment state maintenance efficiency can be increased and a new research idea is provided for making an equipment life management strategy. The model can comprehensively plan an impact of economic connection between different failuremodes on an equipment state detection strategy, and the equipment state maintenance efficiency can be feasibly and effectively increased.