Objective To explore the correlation of tumor growth and endothelial progenitor cells (EPC) entering blood induced by surgical injury in tumor bearing nude mice. Methods Forty-two tumor bearing nude mice were randomly divided into seven groups (n=6): non-surgical injury groups (1 d and 30 d), anesthetic group, surgical injury groups (24 h, 48 h, 72 h and 30 d after surgery). Blood samples and xenograft tumor tissues were taken from anesthetic group 24 h after anaesthesia and surgical injury groups 24 h, 48 h, 72 h and 30 d after surgery. EPC levels in peripheral blood were measured by flow cytometry, serum VEGF levels were determined by ELISA, microvessel density (MVD) and expression of VEGF were detected by immunohistochemistry. Results The levels of EPC in 24 h post-surgery group, 48 h post-surgery group and 72 h post-surgery group were significantly higher than that in non-surgical injury 1 d group (P<0.05). The levels of VEGF in 24 h post-surgery group, 48 h post-surgery group, 72 h post-surgery group and anesthetic group were significantly higher than that in non-surgical injury 1 d group (P<0.05). There was no significant difference in MVD among groups (P>0.05). Pearson correlation analysis revealed that serum VEGF levels were related to EPC levels in peripheral blood (r=0.695 6, P<0.01), while EPC levels in peripheral blood were not related to MVD (r=0.221 4, P>0.05), and serum VEGF levels had no correlation with MVD (r=0.224 9, P>0.05). Conclusion Surgical injury has no obvious influence on xenograft tumor growth.