Abstract: Northwest China mainly belongs to arid and semi-arid region, where water resources are scarce and unevenly distributed spatio-temporally. In the past, a large number of investigations and evaluation of groundwater resources and scientific research were carried out around water use for urban and rural life, industry, agriculture and animal husbandry production, and played a crucial role in the security of water supply. With the increasing impact of global climate change on hydrological and water conditions, the implementation of national strategies, such as the construction of a new development pattern in western China and ecological protection and high-quality development in the Yellow River Basin, the situation of water resources security in northwest China has changed significantly and higher requirements for water supply security have been put forward. Based on the review of existing work and summarization of the development and achievement, it is suggested that the investigation and research should be strengthened in three aspects, including the exploration of underground reservoirs, the exploitation and utilization of brackish water resources, and the joint operation of surface water and groundwater in the future hydrogeology work. Suggestions to solve the problems and meet the challenges from eight aspects are also put forward based on the underground space formed by natural and human engineering activities in this paper.