This study is to investigate the effects of ubenimex on tumor cell invasion and apoptosis, dose relationship and mechanism.  Immunofluorescence staining was performed to detect the expression of CD13 in HT-1080 cells.  MTT assay was used to analyze the effect of ubenimex on cell proliferation.  Annexin V-EGFP/PI was used to detect apoptotic cells by flow cytometry.  Cell cycle was analyzed using flow cytometry.  Ala-pNA was used as substrate to evaluate the effect of ubenimex on the aminopeptidase activity.  Transwell assay was used to analyze the effect of ubenimex on cell invasion and migration ability.  Western blotting was used to detect the expression level of CD13.  MMP activity was analyzed using gelatin zymography.  The results showed that ubenimex at high concentration inhibited the proliferation of HT-1080 cells (IC₅₀: 3.8 mg·mL⁻¹), and induced cell apoptosis.  Cell cycle was blocked at G₁ phase.  Ubenimex at low concentration inhibited the aminopeptidase activity of HT-1080 cells (IC₅₀: 8.3 μg·mL⁻¹) and inhibited cell invasion, but it had no effects on the cell migration and proliferation.  Ubenimex had no effects on CD13 expression and MMP activity.  In conclusion, ubenimex at low concentration can inhibit the invasion ability of tumor cells by directly inhibiting the aminopeptidase activity; ubenimex at high concentration can inhibit the proliferation of tumor cells and induce cell apoptosis by a CD13-independent pathway.