Objective To evaluate and compare the diagnostic validity of MRI and DSA in patient suspected with spinal dural arteriovenous fistula(SDAVF). Methods A retrospective review on clinical data of 25 cases diagnosed as SDAVF was done to analyze the characteristics of SDAVF on both MRI and DSA. Results The sagittal or cornoral plane of the T 2 -weighted MRI could best show the extraspinal vascular abnormalities and secondary anomalies, while the orifices of the SDAVF, feeding arteries, draining veins could be satisfactorily demonstrated on the DSA. Conclusions The diagnosis of SDAVF can be made in directly on DSA findings, MRI can delineate the extraspinal vascular abnomalities and secondary anomalies but not the whole picture.