The invention relates to an express way traffic state distinguishing method and apparatus. The express way traffic state distinguishing method and apparatus are characterized by realizing real-time determination and detection of the real-time traffic state of single lane of the detection section by calculating the Euclidean distance between a real-time traffic state evaluation parameter of single lane of the detection section and the first clustering center of each traffic state; according to the sum of the Euclidean distance of all the lanes of the detection section, determining the real-time traffic state of the detection section, and according to the real-time traffic state of the two adjacent detection sections, acquiring the real-time traffic state of the section unit intercepted by the two adjacent detection sections; and by comparing the accuracy of the off-line traffic state which is determined by means of a maximum method of the sum of grades of membership, with the accuracy of the real-time traffic state which is determined by means of a minimum method of the sum of Euclidean distance, feeding back and adjusting the first clustering center for calculating the real-time traffic state to improve the determination accuracy of the real-time traffic state.