To improve effects of congestion pricing, an impedance function and a traffic assignment model were introduced to explore the traffic redistribution on road network. Yingtian Street in Nanjing city was selected as the virtual charged fee example. The index differences of trip distribution, travel mode split rate, service level and travel speed pre-and-post implementing the pricing measure were used for evaluation. The results show congestion pricing could effectively lead the traffic into redistribution, and improve the traffic efficiency and service level of the network, which point out the valid effect of congestion pricing on traffic improvement. However, the results also show the improvement is not in directly proportional to the charging rate, and could get the best improvement effect when the rate is 5 yuan per time in this virtual pricing measure.