The research of high-efficiency trichromatic phosphors based on vltraviolet/near-ultraviolet (UV/n-UV) excitation is of great significance for the development of white light-emitting diode (LED) applications. A series of Ce3+, Tb3+ or Eu3+ single-doped CaxMgyAlmSinOz (i.e., Ca2Mg0.25Al1.5Si1.25O7, Ca2Mg0.5AlSi1.5O7, Ca2Mg0.75Al0.5Si1.75O7, and Ca20Al26Mg3Si3O68) trichromatic phosphors were synthesized by a high-temperature solid-phase method. The crystal structure and band gap of samples were investigated by Rietveld refinement, crystal structure simulation and density functional theory calculation, and the effect of stoichiometry-regulating crystal field on the luminescent performance was analyzed. High-quality blue, green and red trichromatic phosphors with quantum efficiencies of 28.13, 26.42 and 26.75, fluorescence lifetime of 42.23 ns, 2.88 ms and 2.21 ms, as well as a good thermal stability were selected to compare their luminescent performance. Finally, the prototypes of white LED were fabricated with the trichromatic phosphors for UV chip, and their performance parameters (i.e., luminous efficiency, correlated color temperature and color rendering index) were tested. The results show that these phosphors have a promising potential in the application of UV-excited white LEDs.