Monodispersed LaCO₃OH microgears with a novel plum blossom-like structure are prepared by a simple, reliable, environmentally-friendly and glycerol-mediated solvothermal method for the first time. By studying the effect of the experimental parameters on the morphology of LaCO₃OH structures, we find that urea and glycerol at high concentration play a significant role in the formation of the plum blossom-like LaCO₃OH microgears. In addition, we observe that the morphology evolution of the LaCO₃OH microgears is from wires, spheres composed of rods, to plum blossom-like products with the increase of reaction time. More importantly, PL results demonstrate that the LaCO₃OH microgears show a stronger PL than that of other structures, such as wires and spheres.