<p>In this work, a new system of Ca₉Gd_{0.96−<i>x</i>}Bi_0.04Eu_<i>x</i>(PO₄)₇ phosphor is successfully obtained via high temperature solid-state method and calcined at 1300&#xa0;°C. All samples can be well indexed to the XRD pattern of Ca₉Nd(PO₄)₇ (space group: <i>R3c</i> (161), JCPDS No. 45-0346), indicating the addition of Bi³⁺/Eu³⁺ does not change the structure of the crystal. According to the XPS results, Bi³⁺ and Eu³⁺ are successfully dispersed and stably embedded in Ca₉Gd(PO₄)₇ material. Ca₉Gd_{0.96−<i>x</i>}Bi_0.04Eu_<i>x</i>(PO₄)₇ phosphors show different emission peaks at 420&#xa0;nm (the ³P₁ → ¹S₀ transition of Bi³⁺) and 612&#xa0;nm (the ⁵D₀ → ⁷F₂ transition of Eu³⁺) under near-ultraviolet excitation at 375&#xa0;nm. The intensity of Eu emission varies as the concentration of Eu³⁺, and the emission intensity is strongest when the concentration of Eu³⁺ is about 80 at%. By monitoring the Eu³⁺ emission, a Bi³⁺ excitation band is observed on the PLE spectrum, indicating the occurrence of energy transfer from Bi³⁺ to Eu³⁺, with an efficiency of 65%. Furthermore, the value of critical distance <i>R</i>_<i>c</i> is calculated to be 11.2&#xa0;Å, indicating that the main cause of the quenching mechanism is the multipole interaction. Meanwhile, the energy transfer mechanism of the Ca₉Gd_{0.96−<i>x</i>}Bi_0.04Eu_<i>x</i>(PO₄)₇ samples is primarily controlled by the dipole–dipole interaction. The temperature-dependent (in the range of 300–500&#xa0;K) analysis has been obtained. The emission intensity at 500 K can maintain 63% of the room temperature, and the activation energy <i>E</i>_<i>a</i> is 240&#xa0;meV. The relative high activation energy indicates that the new systems of Ca₉Gd_{0.96−<i>x</i>}Bi_0.04Eu_<i>x</i>(PO₄)₇ phosphors have good thermal stability. The Ca₉Gd_{0.96−<i>x</i>}Bi_0.04Eu_<i>x</i>(PO₄)₇ phosphor developed in this work is an promising candidate for application in LEDs and expected to be widely used in lighting and display applications.</p>