A series of LaOF:Ln(3+) (Ln = Eu, Tb, Sm, Dy, Tm, and/or Ho) nanocrystals with good dispersion have been successfully prepared by the hydrothermal method followed a heat-treatment process. Under ultraviolet radiation and low-voltage electron beam excitation, the LaOF:Ln(3+) nanocrystals show the characteristic f-f emissions of Ln(3+) (Ln = Eu, Tb, Sm, Dy, Tm, or Ho) and give red, blue-green, orange, yellow, blue, and green emission, respectively. Moreover, there exists simultaneous luminescence of Tb3+, Eu3+, Sm3+, Dy3+, Tm3+, or Ho3+ individually when codoping them in the single-phase LaOF host (for example, LaOF:Tb3+, Eu3+/Sm3+; LaOF:Tm3+, Dy3+/Ho3+; LaOF:Tm3+, Ho3+, Eu3+ systems), which is beneficial to tune the emission colors. Under low-voltage electron beam excitation, a variety of colors can be efficiently adjusted by varying the doping ions and the doping concentration, making these materials have potential applications in field-emission display devices. More importantly, the energy transfer from Tm3+ to Ho3+ in the LaOF:Tm3+, Ho3+ samples under UV excitation was first investigated and has been demonstrated to be a resonant type via a quadrupole-quadrupole mechanism. The critical distance (RTm-Ho) is calculated to be 28.4 angstrom. In addition, the LaOF:Tb3+ and LaOF:Tm3+ phosphors exhibit green and blue luminescence with better chromaticity coordinates, color purity, and higher intensity compared with the commercial green phosphor ZnO:Zn and blue phosphor Y2SiO5:Ce3+ to some extent under low-voltage electron beam excitation.