摘要
High-pressure hydrothermal systems (HHSs) occur on many occasions, such as scientific experimentations, and industrial and natural processes. Oxygen fugacity/activity is one of the basic physicochemical parameters of HHSs. It frequently controls the composition species, state and properties of HHSs, and influences the happening and evolution of many HHSs processes. At the end, the prospects for the future development of oxygen fugacity/activity sensors and control techniques in hydrothermal science and technology were presented.