CaAl12O19:Ce-0.06(3+),Eu-x(2+) phosphors were synthesized through a combustion process, and their optical properties were investigated using cathodoluminescence (CL) measurements. The results for the CL spectra showed that different energy transfer mechanisms exist in CaAl12O19:Ce-0.06(3+),Eu-x(2+) and are dependent on the Eu-x(2+) acceptor concentration. As the Eu-x(2+) acceptor concentration increased, the lifetime of the Ce3+ donor decreased, while that of the donor related to the diffusion increased. The dominant energy transfer at low concentrations of the Eu-x(2+) acceptor in CaAl12O19:Ce-0.06(3+),Eu-x(2+) was attributed to the electric dipole-dipole interaction between the Ce3+ donors and the Eu2+ accepters, resulting from the diffusion limited energy migration. While a similar energy transfer mechanism at the high concentrations of the Eu2+ acceptor in CaAl12O19:Ce-0.06(3+),Eu-x(2+) dominated in the transient state part, a different energy transfer mechanism appeared in the steady state part of the decay process.