Tourmaline is a kind of borosilicate mineral with complex structure and composition, which is used in the fields of functional materials, environmental protection and healthcare. Since the positive and negative charge centers of tourmaline do not coincide, tourmaline has a natural spontaneous polarization that is one of the most important properties, having its application in various fields. In previous studies, the changes of element occupancy, valence proportion of key elements and crystal structure parameters in tourmaline cause the lattice distortion, resulting in a change of spontaneous polarization intensity. It is thus of great significance to reveal the relationship among the composition, structure and property of tourmaline. In this paper, the control path along iron speciation-microstructure-spontaneous polarization of Fe-Mg tourmaline was investigated to clarify the structure-activity relationship dominated by cation occupancy in Y-site of tourmaline and propose the optimal configuration of tourmaline with the excellent performance.