The objective of this study was to investigate the changes in phagocytic function and expression quantities of CD11b and tumor necrosis factor-alpha (TNF-alpha) among microglia cells of craniocerebral injury mice. Modified Feeney method was used to establish the craniocerebral injury mice models. Twenty-one male SPF mice were divided into a control group and a trauma group. The scalp was incised and a bone window was opened in the control group without cerebral injury. In the trauma group, the mice were sacrificed after the craniocerebral injury at 1, 3, 6, 12, 24 and 48 h to make frozen sections of cerebral tissues. The phagocytic rate of microglia cells was observed by using fluorescent microsphere. The changes in the expression quantities of CD11b and TNF-alpha were detected by enzyme-linked immuno sorbent assay (ELISA). The phagocytic ability of the microglia cells after the craniocerebral injury increased at 1 h after injury compared with that of the control group (P<0.01). The expression of surface antigen CD11b of the microglia cells and the expression of TNF-a increased at 1, 3, 6, 12, 24 and 48 h after the injury compared with those of the control group (P<0.01). The phagocytic ability of the microglia cells increased. The expressions of CD11b and TNF-alpha were also gradually enhanced in the acute phase after craniocerebral injury, and then gradually decreased to the normal level. The expressions of CD11b and TNF-alpha indicated a high consistency with the changing trend of the phagocytic ability, suggesting that the microglia cells may participate in the regulation of the inflammatory process of the central nervous system through absorbing apoptotic cells and increasing and secreting inflammatory and anti-inflammatory factors.