Hexagonal YBO3 photocatalysts were successfully synthesized by hydrothermal method. The samples were characterized by XRD, SEM, TEM, XPS, UV-vis, photocatalytic performance, photocurrent and electrochemical impedance analysis. The results show that the pH value has a large effect on the formation of the microspheres. The excellent photocatalytic performance for RhB degradation depends on the exposed {1 0 (1) over bar0} facets in which the fitting concentration of oxygen vacancy can prevent the recombination of the photogenerated carriers. Meantime, the {1 0 (1) over bar0} faceted YBO3 microspheres enhance the absorption of irradiation light and present highest specific surface area which can also accelerate photocatalytic activity.