In order to discuss road configuration from the angle of traffic demand, a new method of urban road grade configuration using equilibrium mechanism between trip mode and road grade levels is proposed, and it is based on the probability of trip efficiency. Firstly, considering the functional gradation of the road, the trip mode is taken as the road service object. The concept of road service priority (RSP) is put forward, and the ideal sharing rate of each trip mode on all grades of roads is obtained through the analysis of capacity. Secondly, on the basis of RSP, road network capacity for every traffic mode can be derived, and a new road network gradation optimization model is established taking the least travel time as the object and the match of the capacity and respective traffic need of each trip mode as the subject. Finally, with the example of Weifang city, it can be found that the result confirms the accuracy and feasibility of this model and the new method has great practical values and instructive significance.