High-efficiency yellow-green polychromatic luminescent phosphors Ca2LaTaO6∶Dy3+, Tb3+were obtained by high-temperature solid-state reaction method. The main narrow emission comes from the 547 nm of Tb3+ and a wide excitation band is located in the region of 250~400 nm due to the sensitization of Dy3+. The energy transfer system was constructed by co-doping Dy3+ and Tb3+ into Ca2LaTaO6 (CLTO) matrix. Furthermore, the energy transfer for Dy3+→Tb3+ was confirmed by excitation/emission spectra and lifetime decay curve measurements. The energy emigration is dominated by dipole-quadrupole interaction, and the efficiency can reach 80% or even higher. Under the characteristic excitation of Dy3+, the luminescence color changes from yellow to green by adjusting the relative doping concentration of Dy3+ and Tb3+ based on the energy transfer. The results indicate that Ca2LaTaO6∶Dy3+, Tb3+ phosphor with adjustable emission color has potential applications in phosphor-converted white LEDs.