The continuous spatial scaling model (CSSM) of NDVI based on fractal theory was proposed and implemented. Based on GEOEYE-1 image and taking NDVI as experimental object, the paper studied the availability of fractal methodology for high-resolution image, and discussed the selection of the best reasonable scale-level for establishing NDVI's CSSM. It was concluded that the fractal methodology is suitable for high-resolution RS image. In some definite conditions, the best reasonable scale-level for establishing NDVI's CSSM exists and can be computed. For the fractal methodology, the results in the paper extended its available range of retrievals and image's resolutions.