A new method of balancing the optical path load was presented for optimizing the weight of Dijkstra algorithm in a DWDM wavelength routing optical networks(WRON).This optimized Dijkstra algorithm was applied in the genetic algorithm to obtain the minimal wavelength number under the different path load condition.The optimal wavelength number in the national science fund(NSF) networks of USA was using this optimized and common Dijkstra algorithm,respectively.The numerical computing result shows that the performance of the blocking probability has been improved greatly.The blocking probability can be reduce 36 % and 10 % respectively when the genetic generation is 20 and the number of wavelength is 7.