With the continuous development of the city and the rapid growth of motor vehicle ownership, the urban traffic congestion in Lanzhou is expanding in time and space, and the main roads are in a state of high saturation during peak hours. The problems of environment, energy consumption, safety and the others directly caused by traffic congestion also pose a certain threat to the sustainable, rapid and healthy development of urban economy. By analyzing and judging the current traffic network, according to the overall thinking of "internal join and external expansion, fast optimization, system integration and overall improvement" and the overall principle of "equal emphasis on vertical and horizontal, first longitudinal and then horizontal, smooth traffic, traffic into the network", the urban road network is smoothened and the external bottleneck road network is connected, and the construction of the road network of Lanzhou which is "convenient for people to travel, smooth for the flow of cars, convenient and efficient" speeds up. The reasonable connection and efficient connection of road networks inside and outside the city are realized, and the supporting and leading ability of road traffic to the economic and social development of Lanzhou Metropolitan Economic Circle and Lanbai Economic Zone. The research thinking can provide the reference for the traffic planning of similar cities.