The models and parameters of dynamic simulation components will lead to inconformity between measured trajectory and simulated trajectory. The power system has a large area and many components. Accurately identifying the error tracing area is a challenge. The article proposed a data-driven large power system error tracing method. It defines a disturbance depth indicator and the variance indicator to evaluate the disturbance degree and trajectory variance of components. The two indicators and their constraints help to identify the error tracing area. The article verifies the effectiveness of the proposed method by an IEEE 10 machines 39-node system simulation. The proposed method reduces cost of dynamic simulation validation task and support the block decoupling process.