In order to reduce the traffic accident caused by the deviation of the driver under the complicated road conditions and to improve the driving safety，the exits of urban expressway with five forks were taken as the research object． Based on the driving simulation technology，the driving behavior data was obtained and evaluated with six indicators． The driver's behavior was analyzed from the aspects of driving efficiency and stability under different navigation broadcast wording． The TOPSIS evaluation method was used to select out the optimal broadcast wording． The results show that different navigation broadcasts have different influence on the driving behavior at the five forks of urban expressway． The driving behavior under navigation broadcasts with a moderate amount of information is efficient and stable，and the driving behavior is the worst under navigation broadcasts with too little information．This result indicates that the navigation information needs to be moderate． Broadcasts with little information can easily lead to confusion，while broadcasts with too much information will increase the information load．Both confusion and the increase in information load have a negative impact on driving behavior． This study can provide guidance for the design of the navigation broadcast wording in urban expressways with multiple forks．