Power system state estimation plays an important role in Energy Management System (EMS). To improve the performance of state estimation, a power system state estimation method based on -fuzzy tree ( -FT) is proposed. Taken 500 kV bus of Fuzhou power grid as the research target, the network structure is analyzed to extract the measurement variables information and select the variables, the obtained feature matrix is used as the input of -FT to establish the -FT model of 500 kV bus voltage amplitude, which is made a comparison with other modeling methods. Then, the bad data of measurement variables is used to validate the robustness of the proposed state estimation method. The results show that the method can effectively resist the bad data of measurement variables, and have higher prediction accuracy and robustness. Besides, the bad data can be limited locally to reduce the impact on the entire power grid state estimation. This work is supported by “Thousand Talents Plan” Special Research Grant of State Grid Corporation of China (No. 5206001600A3).