Decision making of guidance unit is one of the key aspects in the implementation of intelligent dynamic route
guidance system(DRGS), which has direct effect on guidance. The mode of guidance information of DRGS is proposed. The proportion and turning rate forecasting method of multi-destination traffic flow on the road where the variable message signs(VMS) locats is designed. Based on the methods mentioned above, the comprehensive guidance information of guidance unit in DRGS is presented. The results and analysis of simulation experiments show the effectiveness of the proposed decision making of guidance unit.