Ankylosing spondylitis (AS) is a chronic inflammatory disease with complex genetic traits. Multiple sequence variations have been associated with AS, but explained only a proportion of heritability. The studies herein aimed to explore potential associations between genomic copy number (CN) variation (CNV) and AS in Han Chinese. Five AS patients were examined with the high-density comparative genomic hybridization microarrays in the first screen test for AS-associated CNVs. A total of 533 AS patients and 792 unrelated controls were examined in confirmation studies with the AccuCopy assays. A significant association was observed between the CNV of HLA-DQA1 and that of AS. Compared with controls, AS patients showed an aberrant CN, and a significantly increased number of patients had more than two copies of HLA-DQA1. Therefore, the CNV of HLA-DQA1 may have an important role in susceptibility to AS in the Han Chinese population.