Abstract: Based on the situation that there are more intersections and interchanges on the distributed first-class highway, to control the clear distance between intersection exit and interchange exit of distributed first-class highway, ensure the realization of the traffic flow conversion function of it, and enhance the guidance to the actual engineering design, the clear distance range between intersection exit and interchange exit of distributed first-class highway was defined for the first time, by analyzing the process of straight, left turn, and right turn vehicles departing from the main line through the interchange exit, the calculation model for the clear distance between intersection exit and interchange exit was established by considering the most unfavorable driving conditions. The traffic flow characteristics were clarified by measuring the vehicle speed, travel trajectory, and vehicle headway. Combined with the driver's heart, physiological characteristics, and measured traffic flow parameters, the minimum clear distance recommended value was calculated. The research results can supplement the shortcomings of the existing research and provide reference for the relevant design of distributed first-class highway.