Aiming at the phenomenon that the mutual interference of mixed traffic of passenger car and truck on expressway，causing the decline of traffic efficiency，the concept of dynamic control of passenger-cargo division lane in highway was proposed based on the passenger and freight lane division method. Taking the i5 expressway in California as an example，the model was established using the vissim software. Three，four and five lanes with different passenger-cargo ratio were simulated under different traffic flow. The control effect of passenger-cargo lane separation was analyzed. And the flow chart of lane separation dynamic control system was drawn. The research results show that the separation of passenger-cargo lane can effectively reduce the average delay of vehicles，and improve the average speed of vehicles. The effective application range of dynamic control system of passenger-cargo separation can be described as，the standard quantity ratio of passenger car to truck for one-way four lane is 1/8～20，the value for three lane is 1/4～20，the value for five lane is 1/12～10.