Objective To investigate the clinical significance of blood lactic acid after surgeries for intracranial tumors.Methods A total of 107 patients with intracranial tumors who were treated from January 2014 to December 2015 were enrolled. Blood gas parameters were measured before surgery and at 0, 3, 6, 12, 24, 48, and 72 hours after surgery, and the blood lactic acid concentrations were recorded. Intracranial pressure (ICP) and mean arterial pressure were measured at 3 hours after surgery. Cerebral perfusion pressure (CPP) was calculated according to the equation of CPP=mean arterial pressure-ICP.Results Some patients experienced varying degrees of increase in blood lactic acid concentration, which was associated with postoperative cerebral hemorrhage and low CCP (P<0.05).Conclusions In patients with intracranial tumors, the increase in blood lactic acid concentration after surgery does not always suggest blood volume deficiency, and dynamic blood lactic acid monitoring has a great significance in evaluating intracranial condition after surgery.