Abstract: Pyrite is one of the most abundant sulfide minerals in nature, often associated with lead, zinc, copper and other high-value sulfide minerals. Activators are normally used to improve the floatability of pyrite that inhibited due to high alkalinity. The influence of activators on the surface properties of pyrite is the key to reveal its mechanisms. This study investigates the crystal properties of pyrite, including its crystal structure, band structure, density of states, Mulliken, electrochemical properties, etc. Taking the evolution of pyrite surface species as the starting point, this study introduces the effects of surface doping, vacancy defects and surface oxidation on its floatability. The activation mechanisms of ions and flotation agents are reviewed: copper and lead ions form active sites for the adsorption of collector on pyrite surface and promote the adsorption of collectors; acid activators remove hydrophilic precipitation and oxidation products on the surface of pyrite; salt activators react with atoms on pyrite surface to change the surface properties and hydrated layer structure, thereby promoting pyrite flotation. The focus on the surface properties of pyrite including observation, characterization, accurate calculation and simulation during activation, can provide a credible scientific basis for the development of efficient and clean activators, rational utilization of resources and environmental protection.