It is important to avoid secondary brain injury after Traumatic brain injury (TBI) in clinical. Cerebral perfusion pressure (CPP) is associated with blood flow into the brain, and indirectly reflects the cerebral ischemia and oxygenation. However, it is invasive and is inconvenient for continuous monitoring. Recently, near infrared spectroscopy (NIRS) has been widely applied for monitoring cerebral ischemia and hypoxia. In this study, we developed a wireless NIRS system to monitor rat's brain in different impact strengths of trauma. Commercial ICP and MAP devices were also used to compare with NIRS parameters under TBI. The Experimental results show all of δCPP, δ [HbO2], δ [HBT], and δ [HbR] were inversely proportional to the increased impact strengths, and the correlations between δCPP, and δ [HbO2] and δ [HBT] are high. Hence NIRS system may be useful for estimating the level of cerebral perfusion pressure non-invasively.