The integrated application of rapid and accurate topological analysis with state estimation is crucial for ensuring the reliability, stability, and efficiency of power systems. In response to this need, this paper proposed an innovative approach to constructing a spatiotemporal “Power Grid One Graph” model using a graph database and achieving fast topological analysis and state estimation. Firstly, a spatiotemporal power grid model was constructed by combining grid topology with temporally dynamic updates of the power grid telemetric and telesignalling. Subsequently, based on the graph model and employing entity mapping, the spatiotemporal node-breaker graph model was generated. Building upon this model, the topological error identification was executed, and a fast topological analysis optimization algorithm considering the functionality of components was utilized to create the corresponding dynamic bus-branch graph model, facilitating graph-based state estimation. Finally, the proposed method on a real power grid system was validated, and the application and performance enhancement of the spatiotemporal power grid model considering topological changes were explored. The introduced method provides theoretical and practical support for the digital transformation of power systems and the developing of digital twin power grids.