The report presents another approach to study the influence of the Er3+ concentration on the properties of nano-upconversion materials NaYF4:Er3+/Yb3+co-doped. Based on the results, we propose the optimal synthesis procedure to realize the nano-upconversion material for biomedical applications. The fabrication experiments, hydrothermal method has been applied. The traditional charactierization methods such as Xray diffraction analysis, field emission scanning electron microscopy imaging, photoluminescence spectroscopy has been employed to provide the structure of the synthesized materials, morphology, and luminescent properties. Via the study of the optical properties, we find influence of Er3+ doping concentration (mole percentages of Er3+ ions/ total moles of rare earth elements) are various from 1% to 3% during synthesizing process. The results indicate that the synthesized materials have spherical shapes with diameters ranging from 100 nm to 200 nm, a β-NaYF4 (hexagonal) phase structure and emitting red radiation under an excitation at 980 nm. The luminescent characteristics of the material show potential for the rapid identification of specific types of pathogens.