The tribological behavior and the mechanism of nano-silicate mineral powder as lubrication oil additive were researched in the article. The tribological behavior of nano-silicate mineral powder with mass ratio 0.6% in lubrication oil 50CC was tested and compared with the lubrication oil 50CC’s by friction wear testing machine. The surface morphologies and elementary compositions of grinding cracks were analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS).The results showed that the friction coefficient is decreased 37.5%, and the lost mass of the upper proof sample reduces 68.75%, the down’s reduces 86.7%, after adding nano-silicate mineral as lubrication oil additive, by comparison to lubrication oil 50CC’s. Under the lubrication oil which has been putted nano-silicate mineral as additive, there is a repairing layer whose material is different from basal body material on the grinding cracks; in addition, Si, Mg and other elements are deposited on the repairing layer. These state that nano-silicate mineral as lubrication oil additive possesses superior behavior of wear resistance, antiwear and self-repairing effects.