With the increase of air traffic flow, aircraft conflicts and delays on hub airports have been complex and challenging in airport surface management for a long time. In this paper we propose a dynamic route optimizing model to decrease the conflicts on the taxiway and enhance the capacity of airport surface operation compared to the current operation mode. A ready-for-departing or just-arrived aircraft which will push back or taxi in should be assigned a shortest path before the action. At the same time the conflicts such as edge conflicts and cross-node conflicts should be considered. After making choice of taxiing route for the departure or arrival aircraft, we can also give an optimization entry taxi-network time based on Genetic Algorithm (GA) to decrease those conflicts. The dynamic optimizing model contributes two aspects: one is to find a shortest taxiway route without edge-conflicts; the other is to give the optimal cross conflict-free time. This model is validated efficiently by the setting of Guangzhou Baiyun airport based on MATLAB software.