CaAl2O4-based phosphors co-doped with Eu2+, Nd3+, and Pr3+ have been prepared by a solid-state synthesis method. Based on the energy transfer between Pr3+ and Eu2+ in the CaAl2O4 host, it was observed that the presence of Pr3+ modifies the shape of the emission spectra and produces an enhancement of photoluminescence intensity. A thermoluminescence measurement has been performed. The results revealed that the concentration of efficient traps decreased with the increase in Pr3+. As Pr3+ and Nd3+ have occupied the different Ca sites, a competition between Nd-Ca(center dot) and Pr-Ca(center dot) exists in the process of arresting Ca2+ vacancies.