Abstract： Objective To investigate the clinical classification and the appropriate treatment strategies for posttraumatic acute diffuse brain swelling.Methods A retrospective study was performed in 45 patients with posttraumatic acute diffuse brain swelling who were confirmed on a CT scan,all of them were monitored intracranial pressure (ICP) after admission,and then determine the clinical classification and the corresponding treatment strategies in accordance with the initial ICP value,and compared the preoperative -postoperative ICP value of patients who underwent craniectomy through Two - sample t - test.Results Initial ICP value were greater than 35mmHg in 33 out of 45 patients,31 cases underwent craniectomy,one case was failed to surgery because of excessive high ICP,one case underwent conservative treatment because the ICP less than 30mmHg after giving bolus intravenous infusions of mannitol.33 patients had different outcome including 18 cases who died,three remained in a vegetative state,two with severe deficits,one with moderate deficits,eight with a good recovery ; 6 cases ( ICP ＞ 25 ～ 35 mmHg) had different outcome including one with vegetative state,one with severe deficits,four with a good recovery,3 of them underwent craniectomy; 6 cases (ICP15 ～25 mmHg) had different outcome including one with vegetative state,five with a good recovery,all of them underwent conservative treatment.Conclusions It can be divided into three types for posttraumatic diffuse brain swelling in accordance with the initial ICP value including severe intracranial hypertension type ( ICP ＞ 35 mmHg) ; moderate intracranial hypertension type ( ICP ＞ 25 ～ 35 mmHg) ; mild intracranial hypertension type (ICP15 ～25 mmHg) ; Early ICP monitoring has a positive effect to determine the treatment of patients with posttraumatic acute brain swelling.