Past, present and future of studies on ore forming fossil hydrothermal systems and hydrothermal uranium deposits have been reviewed. In the past, the studies of ore forming hydrothermal systems focused on water sources and ore sources, but did not on heat sources. Through analysis of present status for the studies of hydrothermal uranium deposits, it is pointed out that the reconsturctions of paleohydrological systems and paleohydrochemical systems, comprehensive studies of ore sources and quantitative modeling of heat sources for the ore forming hydrothermal systems should be paid much more attention to. Further more, the establishment of metallogenic models and ore hunting indicators based on comprehensive researches on ore formation mechanism of hydrothemal deposits by integration of “heat, water and ore sources” can be regarded as one of the most important tasks for the studies of hydrothermal mineral deposits.