Boron deposits of eastern Liaoning occur in a suite of Early Proterozoic metamorphic rocks, with boron orebodies existent in magnesian marble.Tourmalines occur in metaleucogranulite, tourmalite and boron orebodies.Mineralogical study of tourmalines shows that there exist Mg-Fe series and Na-Ca series of tourmalines, that tourmalines are characterized by rich Mg and Ca, and that their FeO/(FeO+MgO) and Na2O/(Na2O + CaO) are all lower than 0.5. Tourmalines from different rocks exhibit different mineralogical features, which reflect different formation environments and hence have important significance in indicating rock forming and ore forming process.Genetic analysis suggests that tourmalines were formed during regional metmorphism of amphibole facies.