Abstract: Objective To explore the characters of disability determination of forensic psychiatry for diffuse axonal injury(DAI) due to traffic accident and its influence on degree of disability so as to provide better clues for such similar cases. Methods From January 2014 to June 2015,total 530 cases of disability determination for craniocerebral injury due to traffic accident were collected and divided into experimental group(combined with DAI,72 cases) and control group(not combined with DAI,458 cases).The sex,age,occupation,degree of education,time interval from injury to determination,Glasgow Coma Scale scores after injury,coma time after injury,head CT and electroencephalogram when determination,the diagnosis of determination and degree of disability were investigated.The retrospective analysis was done by t-test,χ²-test and multi-linear regression. Results There was no statistical differences in age,degree of education,time interval from injury to determination and head CT at the determination between the two groups(P>0.05).There were statistical differences in GCS(Glasgow Coma Scale)scores,coma time,electroencephalogram(EEG) at determination and degree of disability(P<0.05).The degree of disability of the experimental group was 7.92±1.39,and of the control group was 8.72±1.51.There was statistical difference in degree of disability between the two groups(P<0.05).The mild and moderate abnormal EEG,coma time and GCS scores by multiple linear regression analysis were the relative factors for the degree of disability in the experimental group,which accounted for 70.6% of the variety of the degree of disability.The moderate abnormal EEG,coma time and GCS scores were the relative factors for the degree of disability in control group according to multiple linear regression analysis,which accounted for 81.6% of the variety of the degree of disability. Conclusion There are higher degree of disability in craniocerebral injury combined with DAI,which had relations to the mild and moderate abnormal EEG,coma time and GCS scores.There would be positive influences on disability determination if the DAI are better identified.