Abstract: A methodology for capacity analysis using taffic simulation is provided in this paper. The methodology includes five components, they are characteristics analysis, model description, calibration, validation and experiment solution. As an analysis case, basic expressway section is analyzed. The characteristics of traffic flow in basic expressway section and affecting factors on capacity are described. The frame of basic expressway section simulation model is provided. After calibration and validation, the simulation model is proven that its relative error is only within 5 % in predicting the relationship of volume, speed and density. Finally, the capacity of basic expressway section is calculated as 2 200 veh/ h/lane under ideal conditions on the basis of analyzing a serial of simulation experiments.