An up-conversion luminescent material, NaYF4 doped with rare-earth (RE), possessed a high luminescence efficiency and excellent stability. As described herein, a series of hexagonal nano-prismatic NaYF4:Yb3+,Tm3+ up-conversion phosphors had successfully been synthesized through mild hydrothermal method. The influence of hydrothermal time, the content of sodium tartrate, activator, sensitizer and ammonium fluoride on the luminescence properties of the target product were systematically investigated by means of single factor experiments. Based on the single factor experiments, the orthogonal method was used to obtain the optimal preparation conditions of the sodium tartrate/RE mole ratio, the sensitizer Yb3+ ions content, the NH4F/RE mole ratio, and the hydrothermal time which were 0.5, 23%, 11, 13 h, respectively. The fluorescent emission spectra analysis results showed that the strongest blue up-conversion luminescence emission peaks ((1)G(4)-> H-3(6) transition of Tm3+ ion) of the NaYF4:Yb3+,Tm3+ phosphors using sodium tartrate as complexing agent was located at 477 nm under 980 nm near infrared (NIR) laser diode excitation. Finally the target products using different complexing agent were prepared at optimum preparation condition, and characterized by X-ray diffraction, scanning electron microscope. The crystal structure of products using tartaric acid and citric acid as complexing agent was hexagonal, consisting of spheres with 100 nm diameter. (C) 2015 Elsevier B.V. All rights reserved.