For the first time, pure Tb2MoO6 nanostructures were successfully fabricated using Tb(NO3)(3)center dot 6H(2)0 and (NH4)(6)Mo7O24.4H(2)O as a precursor by ultrasonic method and characterized by via X-ray powder diffraction (XRD), Fourier -transformed infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and Energy -dispersive X-ray spectroscopy (EDS). The various parameters such as the type of capping agent, ultrasonic time and power were optimized to achieve the appropriate sample. The results showed that the type of capping agent, ultrasonic time and power can influence on the morphology, size, and purity of the products, respectively. In this work, pure Tb2MoO6 nanostructures observed by PVP as capping agent in ultrasonic time and power of 30 min and 80 W, respectively. Optical property of optimized product was investigated via diffuse reflectance spectroscopy (DRS). The photo-catalytic activity of proposed nanostructure was studied in the presence of various dyes such as Methylene blue, methyl orange, and acid blue 92 as the water pollutants under UV light illumination. At 0.05 g of nanostructure, Methyl orange pollutant destruction was higher than the two other dyes.