Objective Toanalyze the effect of magnetic resonance diffusion tensor imaging (DTI) on the role of the pathological changes of nerve root happened on patients with lumbar intervertebral disc protrusion. Methods We selected 65 cases of patients who had been diagnosed with lumbar intervertebral disc protrusion (bulging lumbar or outstanding), and 65 cases of healthy people selected in physical examination center of our hospital. We carried on the DTI, T2WI, axial T2WI and sagittal T1WI scan to monitor the lumbosacral nerve roots in the apparent diffusion coefficient (ADC) valueand anisotropic score value (FA). Results 15 cases had both sides of nerve root lesions,20 cases had left nerve root lesions and 30 cases had right nerve root lesions in 65 cases of patients with lumbar intervertebral disc protrusion. DTI images showed that nerve fiber bundle area of patients with nerve root interrupt or gathering together was significantly reduced and with significant difference(P<0.05). Conclusion In order to obtain an intuitive imaging basis and quantitative numerical values, clinically lumbosacral nerve roots in DTI can be used to get the diagnosis to patients with lumbar disc.The majority of patients with lumbar disc will result in waist, leg pain and other clinical symptoms. ADC values can be used to provide reference basis for the diagnosis of these symptoms and measure the FA. The two values can indirectly reflect the movement of water molecules in the nerve root.To quantitatively evaluate degree of nerve root of pathological changes, magnetic resonance diffusion tensor imaging is a better choice. It can make functional images on nerve root. The traditional. Mri sequen ce is a good innovation, which is expected to use the advantages of morphology of nerve bundle and area of DTI to diagnose the nerve root disease of patients with lumbar intervertebral disc protrusion.