Intersection as a hub for vehicles to collect,stee and evacuae,is a complex dynamic system,and many factors affect its capacity.System dynamics method was selected to visualize the trends when system parameters changing on the intersection.The causal loop diagrams,system flow diagrams and calculation model of intersection capacity were built based on the analysis of the relationship between the intersection factors.The simulation result by sung the software of Vensim shows that the width of the sections,the intersection's degree of order and driving speed are the main influencing factors on intersection capacity.The intersection capacity can be enhanced from the above three aspects.Among them,the control of intersection speed can be a new way for improvement.