Er3+ and Pr3+ co-doped AlN thin films were prepared by ion implantation, luminescence properties were characterized via cathodoluminescence spectrometer. For Er3+ doped AlN thin films, 410 and 480 nm peaks with higher intensity were observed, and there were other weaker peaks observed at 537, 560, 771, and 819 nm. For Pr3+ doped AlN thin films, 528 nm peak with higher intensity was observed, and there were other weaker peaks observed at 657 and 675 nm. However, for Er3+ and Pr3+ co-doped AlN thin films, a new luminescence peak at 494 nm was observed and was attributed to Pr3+. According to the experimental results, the energy transfer mechanism between Er3+ and Pr3+ in AlN thin films were investigated, the results show that resonant energy transfer exists between 4F7/2→4I15/2of Er3+ and 3P0→3H4 of Pr3+, which results in the new 494 nm luminescence peak of Pr3+