Deep-level defects in silicon carbide (SiC) are critical to the control of the performance of SiC electron devices. In this paper, deep-level defects in aluminum ion-implanted 4H-SiC after high-temperature annealing were studied using electron paramagnetic resonance (EPR) spectroscopy at temperatures of 77 K and 123 K under different il-lumination conditions. Results showed that the main defect in aluminum ion-implanted 4H-SiC was the posi-tively charged carbon vacancy (VC ), and the higher the doping concentration was, the higher was the concentration of VC . It was found that the type of material defect was independent of the doping concentration, although more VC defects were detected during photoexcitation and at lower temperatures. These results should be helpful in the fundamental research of p-type 4H-SiC fabrication in accordance with functional device development.