Sandstone type uranium deposits have become the most important type of industrial uranium deposits globally. Exploration and research have found that, supergene oxidation fluids and deep fluids both involved in some sandstone type uranium deposits. Therefore, it is crucial to exeute “three new” (new areas, new horizons and new types) prospecting through reviewing and clarifing the types of fluid activities in the deep basin and uranium mineralization. In this paper, the research status of deep fluid activities involved in sandstone- type uranium mineralization has been discussed from macro and micro perspectives, based onreal examples. To probe the influence on uranium endowment, the fluid activity from the deep basin is divided into three types: hydrocarbon fluid, magmatic hydrothermal fluid and formation water, and related typical characteristics and recognition marks are summarized, aiming to reveal the spation- temporal link between deep fluid activity and uranium mineralization and the paragenetic variation of uranium minerals, co- associated minerals, ore body morphology and physical properties of ore- bearing sandstone. The results show that the deep fluid activities mainly affect the formation of sandstone- type uranium deposits by providing new ore- forming materials and changing the ore- forming environment. The formation water from the deep basin and geothermal brine related to tectono- magmatic activity have a significant influence on the uranium source and mineralization temperature, while the hydrocarbon- bearing deep fluid activity can efficiently change the environmental conditions, strengthening and/or improving the reduction ability of ore- bearing strata, through the formation of geochemical barriers or superimposed upgrade. Regarding the ore- forming processes, there are obvious differences between deep fluid activities and shallow supergene oxidized fluid involvements. As uranium exploration moves towards deep area, it is necessary to strengthen a refined model with respect to deep fluid activities in uranium ore- forming process, promoting the development of conceptual theory of sandstone- type uranium deposits, and the break through of uranium exploration.