To investigate the synergistic antitumour effect of Clostridium butyricum combined with apatinib on colorectal cancer in mice. Murine colorectal carcinoma cell line CT26.WT cells were xenografted into the skin of BALB/c mice. Tumour-bearing mice were randomly divided into four groups, and given different treatment options (PBS control; C. butyricum; apatinib; C. butyricum + apatinib). Real-time PCR was used to detect C. butyricum content in the intestine of mice given C. butyricum. The effects of various regimens on tumour growth were monitored, and CD31, proliferating cell nuclear antigen (PCNA), Bcl-2 and cleaved caspase-3 expressions in tumour were analysed by immunohistochemistry. C. butyricum combined with apatinib significantly inhibits tumour growth with decreased CD31, PCNA and Bcl-2 expressions, and increased cleaved caspase-3 expressions. Our study confirms that C. butyricum combined with apatinib in the treatment of xenografted colon tumour in mice can significantly inhibit tumour growth and promote cell apoptosis than apatinib alone treatments, providing the reference for clinical treatments.