YVO4:Eu nanocrystalline phosphors were successfully prepared at 400 ℃ in equal moles of NaNO3 and KNO3 molten salts.NaOH concentration and annealing temperature played important roles in phase purity and crystallinity of the nanocrystallines,and the optimum NaOH concentration and annealing temperature were 6∶40 and 400 ℃,respectively.The nanocrystallines were well crystallized with a cubic morphology in an average grain size of 18 nm.Upon excitation of the vanadate groups at 314 nm,YVO4:Eu nanocrystallines exhibited the characteristic emission of Eu3+,which indicated that there was an energy transfer from vanadate groups to Eu3+.Moreover,the influence of superficial effect,especially the dangling bonds on the structure and luminescent properties of the nanocrystallines was discussed in detail.