Objective: To investigate the effect of octreotide on the subcutaneously implanted tumor mass derived from human cholangiocarcinorma QBC939 cells in nude mice and its possible mechanism. Methods: Twelve nude mice bearing tumor mass composed of human cholangiocarcinorma cancer QBC939 cells were equally randomized into the experimental group and control group. Mice were given respectively octreotide of 100 μg/(kg·d) or normal saline of the same volume by subcutaneous injection with a once-daily regimen for 4 weeks. Mice were sacrificed 24 h after the last dose injection and the tumor masses were resected en bloc. The volumes and weights of the tumors were measured, and tumor inhibition rate of the experiment group was calculated. The expression of hypoxia-inducible factor 1α (HIF-1α) and microvessel density (MVD) in tumor tissues of both groups were detected by immunohistochemical method. The apoptosis in tumor tissues of both groups was detected by TUNEL assay. Results: The size and weight of the implanted tumor in experiment group were significantly reduced compared with control group [(1934.85±272.88) mm3 vs. (2834.63±521.86) mm3; (1.77±0.23) g vs. (2.44±0.65) g] (both P<0.05), and the tumor inhibition rate of experiment group was 29.20%. The expression level of HIF-1α and MVD in the tumor tissues of experiment group were significantly less than those of control group [(0.2605±0.0406) vs. (0.3284±0.1008); (13.61±1.87) vs. (17.44±2.24)] (both P<0.05). The apoptotic index (AI) of tumor issues in experiment group was significantly higher than that in control group (P<0.05). Conclusion: Octreotide has inhibitory effect on the growth of implanted tumor of human cholangiocarcinoma in nude mice. The mechanism may be relevant to induction of apoptosis and inhibition of antiangiogenesis in tumor cells.