Constructing core-shell structures can effectively reduce the surface quenching effect of luminescent?materials, which become an effective method to enhance upconversion luminescence. In this work, a series of NaLnF4@NaLnF4 (Ln=Y3+, Yb3+, Ho3+) core-shell microcrystals were successfully synthesized based on epitaxial growth technology so as to enhance and regulate the upconversion emission of Ho3+ ions. The results of the XRD and SEM indicate that the NaLnF4@NaLnF4 core-shell microcrystals had a pure hexagonal-phase crystal structure with a rod-like shape. Meanwhile, found that the epitaxial growth direction of the micro-shell is not affected by the crystal characteristics in the core, but is determined by the crystal characteristics of the shell. Under 980 nm near-infrared laser excitation, the upconversion luminescence properties of a single microrod with different core-shell structures were investigated via a confocal microscope spectroscopy test system. It is found that in the NaLnF4 micro-crystal, the coated NaYF4 inert shell can also effectively reduce the quenching effect on the surface of the micro-crystal for enhancing upconversion emission. When the Yb3+ ions are introduced into NaYF4 or NaYbF4 active shell is coated, the Yb3+ ions in the shell can effectively transfer excitation energy to Yb3+ in the core through energy migration, and then establish new energy transfer channels realize Ho3+ ion luminescence enhancement. For NaHoF4@NaYbF4 core-shell microrods, the Yb3+ in the shell can transfer more excitation energy to Ho3+ ions at the adjacent interface for enhancing the overall luminescence intensity, and its higher red-green ratio is mainly due to the occurrence of the cross-relaxation process between Ho3+ the ions at high doping concentration of Ho3+ in the NaHoF4 core. Meanwhile, the luminescence process of the micron core-shell system is further confirmed based on the luminescence characteristics of different structures and the dynamic luminescence process. It can be seen that by constructing different micron core-shell structures and introducing sensitizing ions, not only can effectively enhance the luminous intensity of the micron materials, but also the output color can be adjusted. Therefore, this research is an important experimental reference for enhancing the luminous intensity of the micron system and the precise adjustment of luminescence, and can effectively expand the application prospects of micron crystals in the fields of displays, micron lasers and anti-counterfeiting.