A comprehensive evaluation and analysis system integrating the real-time measurement, influencing factors and power flow constraints is established to evaluate the accuracy of the state estimation (SE) results of the actual power system with unknown true values. The accuracy of the SE is evaluated from three dimensions: self, causality and space. First, the respective deficiencies of three dimensions and their mutual relationships are expounded to explain the establishment reasons of the system. Secondly, each dimension is discussed in detail. A holistic indicator based on the real-time measurement, a comprehensive indicator system based on the influencing factors, and an auxiliary indicator based on the satisfaction degree of power flow constraints are established. Then, the quantitative solution of each indicator score and weight is given, and the total score is obtained by combining the indicator weight. Finally, the proposed SE accuracy evaluation system is applied to the IEEE-9 node system. Simulation results show the effectiveness and superiority of the proposed evaluation system. It could avoid the situation where a single indicator has high scores but poor accuracy, and could also indicate the reasons for the evaluation results combined with the sub-index of the influencing factors.