Zn isotopes is a new geochemical tracer, and a prerequisite for using them to constrain some important geochemical processes lies in the adequate understanding of the processes and mechanism of Zn isotope fractionation. This paper presents a review of current understanding of mass fractionation processes in low temperature environments, which include adsorption, precipitation, diffusion, reduction and biological processes. During the process of carbonate precipitation, the precipitates are depleted in heavy Zn isotopes; the mass fractionation increases with the increasing of diffusion distance; metallic Zn reduced from Zn( Ⅱ)aq is enriched in light Zn isotopes; during biologically related processes, the heavier Zn isotopes are preferentially adsorbed on the surface of diatoms, whereas lighter Zn isotopes are preferentially utilized for biological metabolism.