Objective:To explore the value of diffusion tensor imaging(DTI)in radiologically evaluating cerebral small vessel disease(SVD). Methods:Forty-three cases of SVD were imaged with conventional MRI and DTI. Fifty-one lesions in 43 cases were recruited in our study. Average diffusion coefficient(DCavg)and fractional anisotropy(FA)were measured symmetrically and statistically analyzed,which were at level of the lesion and the posterior limb of internal capsule and the cerebral peduncle of the affected and contra-lateral sides. The structure images of cortical spinal tracts(CST)were obtained by diffusion tensor tractography(DTT). Results: There presented three conditions of CST on DTT:CST was showed to run naturally and have a complete structure form in 41/51 lesions,and to be pressured and shifted in 9/51 ones and interrupted in 1 lesion. Both DCavg and FA values of the affected side were different significantly from those of the contra-side(P < 0.05),and the DCavg value is negatively associated with FA value(P < 0.05). The FA values between chronic lacunar infarction and chronic ischemic focus were significantly differentiated(P < 0.05). Conclusion:DCavg and FA values of lesions in SVD changed regularly,and DTT could have a great contribution to estimate the extent of damage to CST in SVD.