Aim: The goal of this study was to investigate the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in rat models of pressure ulcer and to assess their significance. Methods: Sixty-four rats were randomly divided into 8 groups with 8 rats in each group. A pressure on the muscle and skin was produced by embedding an iron piece under the gluteus muscle and placing a circular magnet on the body to generate local tissue ischemia. The magnet was removed after each pressure for 2 hours, followed by blood perfusion for 0.5 hours. These steps were repeated for 5 cycles every day and the steps were repeated in the next morning to establish pressure ulcer models in rats with different stages. MMP-9 and TIMP-1 expression in the pressure ulcer tissues were determined by immunohistochemistry. Results: There was no detectable expression of MMP-9 and TIMP-1 in the pressure ulcer tissues of the blank and control groups. With progression of the pressure ulcer, MMP-9 expression gradually increased, while TIMP-1 expression first increased but then decreased. Conclusions: Increased MMP-9 expression and the imbalance of MMP-9/TIMP-1 expression may contribute to the initiation and progression of pressure ulcer.