Disclosed is a method of reorganizing a wavelength division multiplexing network using dynamic watermarks and a computer readable recoding medium for storing a program for executing the same method. The reorganization method of organizing a wavelength division multiplexing (WDM) network using a dynamic watermark of the invention includes the steps a) collecting load information for optical paths of the WDM network from nodes on the optical paths; b) detecting optical paths having maximum load and minimum load from the collected load information and computing a maximum value and a minimum value based on the collected load information; and c) resetting an upper watermark and a lower watermark based on the maximum value and the minimum value.