It is significant to reveal the development of urbanization pattern in western China and analyze its determinants for promoting the development of new urbanization in China. In this paper, based on the urbanization data of western China from 2005 to 2015 and the geographic detector model, the author analyses the development pattern and determinants of urbanization. The results show that the urbanization rate in western China has increased in the past 10 years, with Chengdu-Chongqing region changing greatly and Qinghai-Tibet Plateau changing minimally. In terms of determinants, economic factors tend to dominate, policies and natural factors are in the leading position, while population quality and spatial factors have relatively little influence. Then, this paper puts forward countermeasures, that is, we should not only develop urbanization, but also attach great importance to the differences in the spatial pattern of urbanization in the western region. China should follow a scientific path of urbanization development under the guidance of the government, and promote it with new industrialization and agricultural modernization, so as to realize their coordinated development. In short, a reasonable analysis of the development pattern and determinants of urbanization in the western region of China can guide the development of urbanization, so as to enhance the economic development in the western China.