Abstract: With wide distribution and large quantity in grid, circuit breaker has great demand for lean maintenance and operation, while increasing revenue and reducing expenditure for enterprises. Based on the idea of digital transformation, this paper emphasizes the utilization of grid data and proposes an evaluation model for circuit breaker’s state, establishing 3D properties for the device, as risk factor, probability and consequence. The model carries out quantitative assessment of the device’s state from historical data, accident severity, problem rectification and other aspects. The study aims to provide data support for the scientific maintenance and operation of circuit breaker, reduce safety risks and improve management benefit for grid enterprises.