Sphere-like and cauliflower-like hexagonal-vaterite LuBO3 have been successfully synthesized for the first time via a chemical conversion route using Lu(OH)CO3 colloid spheres as sacrificial precursor and H3BO3 as boron source without any additional surfactant. FTIR analysis provides an additional evidence of the formation of vaterite-type LuBO3 in this method. It was found that, an appropriate amount ethanol in the hydrothermal process has a great effect on the products' morphology and crystallinity. Time-dependent experiments indicate that the formation of LuBO3 crystals went through a two-stage growth process, which involves a fast nucleation of primary particles followed by a slow aggregation and crystallization of primary particles. An investigation on the photoluminescence (PL) properties of LuBO3:Eu3+ phosphors with different morphologies indicates that their PL intensity are dependent on their crystallinity. The effect of Eu3+ and Tb3+ doping concentration on PL intensity were also investigated and the quenching concentration of LuBO3:Eu3+ and LuBO3:Tb3+ is 0.25 and 0.20, respectively. Moreover, for Eu3+/Tb3+ doped LuBO3 phosphors, the color tones can be tuned from green, through green–yellow and yellow, and then to red by simply adjusting the relative doping concentrations of the Tb3+ and Eu3+ ions.