Dodecahedral SmVO4 nanocrystals with uniform size had been successfully synthesized by a facile hydrothermal process in the presence of potassium hydroxide and urea. The dodecahedron-like SmVO4 was characterized by X-ray diffraction, field-emission scanning electron microscopy, Fourier transform infrared, X-Ray photoelectron spectroscopy, high-resolution transmission electron microscopy and photoluminescence. The possible growth mechanism of the SmVO4 nanocrystals with dodecahedral shape was discussed. Under excitation at 315 nm, the SmVO4 sample exhibits strong orange emission while it as the host doped with suitable amount of Eu3+ ions shows strong reddish orange emission. The diversity in emission intensity detected from SmVO4: x% Eu3+ (x = 1, 3, 5, 7) was compared. The hydrothermal method for preparing dodecahedral SmVO4 nanocrystals provides us an idea to synthesize other rare earth orthovanadate nanomaterials with special morphology and interesting optical property.