Abstract: Objective To study the application of thin-slice short tau inversion recovery（STIR） sequence in brachial plexus magnetic resonance imaging. Methods Six patients（3 males and 3 females） at the age of 17-46 years underwent coronal MR scan of brachial plexus using both conventional T2WI and STIR sequences on 1.5T MR scanner.Multi-plane reconstruction（MPR） and maximum intensity projection（MIP） were performed based on STIR source images to get random angle reconstructive coronal images of brachial plexus.Images of brachial plexus on both conventional T2WI and STIR sequences were observed.The number of clearly visualized spinal nerve roots and trunks and the mean length of brachial plexus were calculated. Results The number of clearly visualized roots and trunks in 12 brachial plexuses（60 roots and 36 trunks） was 56 and 33,respectively,with a mean length of 168mm,on reconstructive STIR images,and was 51 and 24,respectively,with a mean length of 109mm,on conventional T2WI images. Conclusion STIR can clearly show the roots and trunks of brachial plexus.