In 2035, China will basically realize socialist modernization. In the new journey of building a socialist modern country in an all-round way, as a relatively backward area, the western region should work hard, accelerate the modernization progress, and make efforts to basically realize the modernization earlier. Based on such five dimensions as economic modernization, social modernization, urban and rural modernization, ecological civilization and political civilization, this paper constructs a modernization level evaluation index system and analyzes the basic situation in modernization construction in western twelve provinces and districts and municipality in 2019. The results show that in the modernization construction in the western region, there is a significant difference between the western region and the eastern region, furthermore, there is an obvious difference between each province as well as between the northwest region and the southwest region, and there is the heterogeneity in different dimensions. Currently, there are many constraint factors for the western region to basically realize the modernization such as weak innovative development power, low industrial structure level, high pollutant emission level, an obvious gap between different regions and between urban and rural areas, and human resource quality, local governance capacity and social security capacity need to be improved. Therefore, the western region should actively implement the innovation-driven development strategy, the balanced and coordinated development strategy and the talent-led development strategy, cultivate and stimulate the innovation momentum to promote the optimization and upgrading of industrial structure, achieve regional coordinated development and urban-rural integration, and cultivate and use the quality advantage of human resources. At the same time, it is necessary to strengthen the restoration and protection of the ecological environment and promote the transformation of the mode of production into a green one, deepen institutional reform, modernize local governance capacity and systems, and improve the supply of public services.