Abstract： Objective To explore the value of CatWalk-assisted gait test in evaluating the changes of motor function in the rat models of traumatic brain injury.Methods Improved Feeney tree fall brain damage device was employed to establish the craniocerebral injury rat models; injured loci were located in the right side of the brain cortex; CatWalk-assisted gait test and mNSS were performed on the 3rd,7th,14th and 28th d of injury.SPSS 13.0 software was used to compare the scores of the above tests.Results Significant differences on each parameter of the left hind limb were noted between the day before injury and the day of 7 d after injury(P＜0.05); and significant differences were also noted between left and right hind limbs(P＜0.05).Significant differences on such motion parameters as maximum contact area,contact strength,claw length and walking cycle in the left and right fore limbs were noted between the 14th d of injury and before injury(P＜0.05); and the walking cycle,average intensity and time of claws leaving the flat between two steps in these rats were signficantly different between the 14th d of injury and before injury(P＜0.05.No significant differences on each motion parameter were found between the 3rdand 28th d of injury(P＞0.05).Significant differences on mNSS scores were noted between the day before injury and the 3rd,7th 14th,and 28th d of injury(P＜0.05); and the mNSS scores on the 3rd and 7th d of injury were obviously higher than those before injury.Conclusion Catwalk-assisted gait test can accurately detect the changes of motor function,enjoying an important significance in the study of behavior of rat with traumatic brain injury.