During the 14th Five-Year Plan period, Gansu Province has planned to construct the Lanzhou Metropolitan Area with Lanzhou City as the core and its adjacent municipal areas as the hinterland. With the rapid construction and layout of regional transportation facilities, the external transportation pattern of the Lanzhou Metropolitan Area has gradually taken shape. Based on the big data of population migration within the metropolitan area, the current situation of transportation between cities was studied, and the integrated layout of transportation facilities was optimized. The results of the characteristics of the inter-city travel network of residents constructed based on different time periods and different transportation modes indicate that the overall travel network of regional residents presents a “radiation-shaped” pattern centered on Lanzhou. The travel scale and stability of the routes between Lanzhou and the cities in the hinterland are large, while the connections between the hinterland cities are relatively weak. Compared with the daily period, the travel intensity during special holidays and the “Spring Festival travel rush” increases, but it is still dominated by large-scale daily routes. Road transportation is the main mode of regional travel. Conventional railways no longer meet the needs of rapid inter-city travel, while high-speed railways promote large-scale inter-city travel. Based on the current characteristics, optimization strategies for the transportation integration of the Lanzhou Metropolitan Area are proposed respectively from the three transportation modes of aviation, railways, and roads to promote regional coordinated development.