Ankylosing spondylitis (AS) is a chronic and progressive autoimmune disease affecting the invasion of the spine, sacroiliac joints and peripheral joints. T cells play a vital role in the underlying pathogenesis of AS, which mediated autoimmune and inflammatory responses via specific recognition of autoantigen peptides presented by susceptibility HLA. Antigen-specific T cells triggered by HLA/antigen complexes will undergo a massive expansion that forming an uneven T cell repertoire. To enhance our understanding of T-cell-mediated autoimmune in AS, we applied TCR β chains high-throughput sequencing to AS patients for in-depth TCR repertoire analysis. A significantly lower TCR repertoire diversity was observed in peripheral blood of AS patients relative to controls. And severe patients in our AS cohort have a more restricted TCR repertoire than mild patients, suggesting that the TCR repertoire diversity might be associated with the clinical severity of disease. No V, J and VJ pairs with significant biased usage were identified, which indicated that the usage frequency deviation of certain V/J/V-J genes in AS patients is little. This is a pilot study with potentially interesting observation on reduced diversity of T cells repertoire in peripheral blood of AS patients and further studies are needed.