Route guidance system is one of the essential components of a vehicle navigation system in ITS. In this paper, a centrally determined route guidance system is established to solve congestion problems. The Sarsa learning method is used to guide vehicles, and global and local parameter strategy is proposed to adjust the vehicle guidance by considering the whole traffic system and local traffic environment, respectively. The proposed method can save the average driving time and relieve traffic congestion. The evaluation was done using two cases on different road networks. The experimental results show the efficiency and effectiveness of the proposed algorithm.