Since the urban extraction based on the visible light red band and the urban index method based on the visible light green band are easily confused with the water body and bare land, we propose a method to consider the yellow band of the new extraction index (NBAEI) in urban areas. The function of the extraction index is to use the positive and negative characteristics of the reflection difference between the yellow and red wavelengths in an urban area, distinguish the urban area from the water body, and widen the difference between the bare land and the urban area while extracting the urban area. Baoji city, Rizhao city, and Baoding city are used as study areas, and three types of indicators are analyzed: overall accuracy, misclassification accuracy, and omission accuracy. Experimental results show that the overall classification accuracy of the NBAEI method is higher than the other two methods. The accuracy of misclassification and omission is lower than the other two methods, indicating that the proposed method is very accurate, effective, and suitable for extraction. The urban area is extracted from the GF-6 satellite.