The RGB remote sensing images and DEM data were used, and the Sobel operator method, artificial interactive threshold segmentation method, DEM river network method and object-oriented classification method were adopted to extract waterline information and calculate fractal dimension of Yangling Section of the main stream of Weihe River. The results showed that the coefficient difference of the fractal dimension equation of the waterline extracted by different methods is not obvious, and their extraction effect was good The artificial interaction threshold segmentation method has a relatively higher extraction precision, and the high-resolution RGB remote sensing image can be safely used for the waterline information extraction. The fractal dimension of the study area was between 1.0 and 1.4, which means the Yangling main stream is at the infancy of the erosion development. The four methods tested in this paper were all feasible to extract waterline. With the absence of high-precision DEM data, an RGB remote sensing image can also be used to extract waterline information.