Abstract: The water extent parameter of Poyang Lake is significant to reveal the ecological environment evolution and drought formation mechanism of the basin. In dry season, the terrain features of Poyang Lake are complicated and discontinuous, the microscopic formation mechanism of water body are highly complicated and diverse, so the spectral features of water body and adjacent terrain are complicated and the existing water body extraction approaches are difficult to meet the extraction efficiency and accuracy requirements of water body with highly landscape heterogeneity. Decision tree method，threshold method and region growing method were combined to perform water extraction by using HJ-1 data. Then, the accuracy validation and efficiency evaluation were performed by using the manual interpretation results as reference. The results indicate that the method significantly improved the efficiency, only 2 hours required instead of 2 days by using traditional visual interpretation method. The correct recognition accuracy of the method reaches 95.8% of the visual interpretation.