Abstract: The large relative weight contrast between ¹⁰B and ¹¹B leads to an obvious boron isotopic fractionation in the nature. Boron is soluble in water and is chemically active. So, the boron isotopic composition is diverse in different environments. The variation of boron isotope composition (δ¹¹B) in nature ranges between -70‰ and +75‰. The negative δ¹¹B values are found in non-marine evaporite borate minerals and certain tourmalines, while positive δ¹¹B values are common in salt lake brine and evaporated seawater. Since the 1980s, with the establishment and improvement of the measuring method of boron isotope, the geochemical researches of boron isotope are increased rapidly. At present, the boron isotopes are successfully applied to determine depositional environments and ore genesis, trace groundwater pollution and seawater intrusion, reconstruct ancient marine environment and study continental chemical weathering, etc. This paper studied the mechanism of boron isotopic fractionation, summarized the distribution of boron isotope in nature, reviewed the achievements and the problems, and finally proposed the research direction of boron isotope in geochemical fields, in order to shed some lights on the further development of boron isotope in the future.