In March 2018, the Chinese National Development and Reform Commission issued the Lanzhou-Xining Urban Agglomeration Development Plan (hereinafter referred to as the “plan”), which proposed for the first time to build a regional urban agglomeration in Northwest China from the national level. Lanzhou, Xining and their surrounding areas are located at the junction of the Qinghai-Tibet Plateau and the Loess Plateau in China. They are relatively densely populated areas with relatively superior natural conditions in Gansu and Qinghai province. They are also the important hubs connecting the central regions to the western regions of China. The “plan” proposes that the Lanzhou-Xining urban agglomeration should be cultivated and developed into an important urban agglomeration supporting the pattern of territory security and ecological security and maintaining the prosperity and stability of Northwest China. In China’s urbanization strategy, Lanzhou-Xining urban agglomeration, which is still in the cultivation stage, is a regional urban agglomeration in Northwest China. Compared with the role of the developed areas as the engine of China’s economic development, Lanzhou-Xining urban agglomeration also has its special historical mission and major responsibilities of maintaining territory and ecological security, promoting national unity, ensuring people’s livelihood and happiness. Based on the cognition of the “space of place” of this urban agglomeration, this paper analyzes the city network characteristics of Lanzhou-Xining urban agglomeration and explores the optimization path of regional spatial pattern of Lanzhou-Xining urban agglomeration by constructing three types of urban network from the perspective of “space of flows”. The main conclusions are as follows: The characteristic analysis of the three types of networks shows that Lanzhou and Xining are the main and sub centers of the city networks, and the network pattern in the east area is strong and the east area is weak. At present, Lanzhou-Xining urban agglomeration is in the early stage of network development, and its resource elements aggregation, infrastructure configuration and industrial development layout have not been finalized, especially for the central cities such as Lanzhou and Xining, the urban space development is still in the expansion period, and strategic deployment has been made for the bottleneck problems of their own space development. For example, the construction of Lanzhou New Area, Xining Duoba New Area and Haidong Hehuang New Area all are far away from the original central city, so the overall spatial structure of the central city will have obvious changes in the future. In addition, the improvement of modern regional transportation and communication facilities such as high-speed railway, expressway and Internet will also make a systematic and networked regional spatial structure. For the western region of China, it is undoubtedly an important way for the region to move towards a high-quality development pattern with the ecological and agricultural security as the background, the energy accumulation of urban nodes as the basis, and the improvement of functional network as the basis. Under the background that ecological conservation and high-quality development of the Yellow River basin has become a national strategy, the following aspects should be paid attention to in optimizing the regional spatial pattern of Lanzhou-Xining urban agglomeration. First of all, the central city needs to improve the quality and capacity, reasonably layout the strategic space area of the central city, and enhance its radiation capacity; at the same time, the Lanzhou-Xining urban agglomeration needs to strengthen the construction of secondary central city, improve the regional urban system, and form a multi-level urban system of “central city-secondary central city-support node”, and jointly promote the formation of an efficient development of modern metropolitan area. At the level of metropolitan area, there are strong small cities in the periphery of Lanzhou-Baiyin metropolitan area, such as Dingxi and Linxia, after the completion of the high-speed railway, Baiyin will enter Lanzhou’s 1-hour commuter circle, which will greatly promote the process of integration process of Lanzhou and Baiyin. While, in Xining-Haidong metropolitan area, although high-speed rail has been operated between Xining and Haidong, it is still necessary to actively strive for and plan the construction of intercity rail line network to create the Great Xining, so as to effectively connect with the gateway areas such as airport and airport logistics park, and strengthen the functional convection between regions.