As an important platform for participating in international competition and cooperation, supporting economic growth and promoting coordinated regional development, urban agglomeration plays an important role in China’s economic, social and urbanization development. At this time, the Guanzhong Plain urban agglomeration (GZPUA), as the second largest urban agglomeration in western China, has a moderate population density. The high demand and high input of resources for population growth make the regional ecological destruction and environmental pollution more prominent. Therefore, it is of great practical significance to study the coordinated development of urbanization and ecological environment in GZPUA. By using the panel data of the GZPUA of China between 2008 and 2017, this study constructed evaluation index system of new-type urbanization and ecological environment quality and calculated the weights of the indices within the evaluation system via the improved entropy weight method, finally determined the new-type urbanization and ecological environment quality of each city. Then the coupling coordination degree model was used to analyze the coupling coordination relationship between two systems of GZPUA and their coupling stages and levels. In addition, the driving mechanism of their coordination degree was explored by using geographic detector method. The results show that: 1) The GZPUA new-type urbanization quality is characterized by both slow growth except Xi’an by a rapid increase. The ecological environment quality is characterized by both slow growth and fluctuations, except Qingyang by a decrease. There are spatial differences between the quality of new-type urbanization and the quality of ecological environment. 2) The 11 cities can be divided into high-high type (Xi’an), high-low type (Xianyang, Yuncheng, Linfen), low-low type (Pingliang, Weinan), and low-high type (Shangluo, Tianshui, Qingyang), different types should take different development paths. 3) The coordination degree between urbanization and ecological environment quality in GZPUA showed an upward trend, and formed a spatial distribution pattern with Xi’an as the core and decreasing to the outer circle cities, with regional differences. 4) The coordinated development of new-type urbanization and ecological environment is a process in which various driving factors act on different driving forces. These driving forces can be summarized as market driving force, endogenous driving force, outward driving force and administrative driving force. Based on the current situation of coordinated development of new-type urbanization and ecological environment in the GZPUA, it is recommended to promote the coordinated development of urbanization and ecological environment according to local conditions, strengthen the urbanization market mechanism, and optimize the industrial layout. Further, guide the flow of various factors across regions, strengthen technological innovation on the basis of breaking regional divisions, narrow the gap between urban and rural areas, establish the concept of coordinated development, and give play to the government’s “visible hand” role.