Objective To study whether carbon dioxide used to establish pneumoperitoneum has an influence on port-site and intraperitoneal implantation and metastasis of tumor cells. Methods R15 hepatic cancer cells were injected into 30 Wistar rats’ peritoneal cavities 1 hour before operation, then the 30 Wistar rats were randomly divided into 3 groups: gasless group, helium group and carbon dioxide group. The suspension was exposed to the gas environment for 2 hours, all animals were killed after 28 days and the port-site and intraperitoneal implantation and metastasis of tumor cells were examined. Results On port-site, intestinal serous coat, mesentery, greater omentum and diaphragm, the weights of tumor cells, in carbon dioxide group were (326.7±230.3) mg， （626.2±215.9） mg，（476.2±204.8） mg，（2 536.5±906.7） mg and （384.5±149.9） mg respectively； in helium group were (235.6±107.3) mg， （414.2±148.4） mg, （261.8±92.6） mg, （1 633.4±247.3） mg and（220.0±57.9） mg； in gasless group were (145.0±42.4) mg， （221.5±108.2） mg， （212.5±109.6） mg, （797.5±335.9） mg and 113.0 mg.The weights of carbon dioxide group showed a significant increase, compared with helium group and gasless group (P＜0.05). The weights of helium group were greater than gasless group，but there was no significance in statistics (Pgt;0.05). Conclusion The insufflation of carbon dioxide promotes intraperitoneal tumor implantation and growth compared with helium and gaslessness in a rat model.