Objective To explore the clinic application value of ultrasonography examination of optic nerve sheath diameter(ONSD) in brain injury.Methods From July 2008-June 2011,90 cases of brain injured patients were chosen as experimental group including light (A group),medium (B group),and heavy (C group) brain injured patients according to the admission GCS score ;50 cases of conventional physical examination and 90 cases of volunteers 50 in neurosurgical outpatient were chosen as control group.The ONSD of both groups were measured 3 mm behind the globe through orbital using color sonographic with different time after admission.3 times measurements were carried out for every optic nerve sheath.All client's ONSD mean and standard deviation were calculated.In 0.5 h after color dopplar ultrasound examination,lumbar vertebra puncturing measured intracranial pressure in different groups.Results After admission (1d,3 d,7 d,14 d),the ONSD of A group was (4.54 ±0.32)mm,(4.42 ±0.30)mm,(4.44 ±0.32) m,and (4.43 ± 0.25) mm,respectively; The ONSD of B groups was (4.48 ± 0.28) mm,(4.52 ± 0.24) mm,(4.46 ±0.28)mm,and (4.38 ±0.22)mm,respectively; The ONSD of C group was (5.67 ±0.35)mm,(6.36 ± 0.42) mm,(5.65 ± 0.23) mm,and (4.76 ± 0.35) mm,respectively.After admission (1 d,3 d,7 d,14 d),the intracranial pressure (IP) of A group was (82 ± 11) mmH2O,(79 ± 12) mmH2O,(90 ±15) mmH2O,and (86 ± 14) mmH2O,respectively; The IP of B group was (78 ± 15) mmH2O,(85 ± 10)mmH2O,(78 ± 16) mmH2O,(80 ± 11) mmH2O,The IP of C group was (225 ± 26) mmH2 O,(288 ± 23)mmH2O,(256 ± 23) mmH2O,(122 ± 18) mmH2O,respectively.Group D had the ONSD average of (4.58± 0.41)mm and IP of (88 ± 10)mmH2O after eyeball 3-mm place.No difference was found between A and B,A and D,or B and D (P＞0.05) ; A difference was found between A and C,B and C,or D and C (t =12.24～24.67,P＜0.01).Conclusions The ONSD and IP in light medium brain injured patients had no change.In patients with severe brain injury,IP changed with the time after injury,the ONSD increased with the IP,the ultrasonography examination of ONSD with the important value in the diagnosis and treatment can respond the IP increase,which is a non-invasion,convenient,fast,and feasible method for evaluation of cranial high pressure.