Objective: To observe the expression alterations of SM22α, osteopontin (OPN) and cytoskeletal proteins including α-SMA, β-tubulin and desmin in human abdominal aortic aneurysm (AAA) tissues. Methods: The tissues from normal abdominal aortic wall and AAA wall were harvested, and then mRNA and protein expression levels of SM22α, OPN, α-SMA, β-tubulin and desmin in the two types of tissues were determined by real-time PCR assay and immunohistochemical staining, respectively. Results: Compared with normal abdominal aortic tissue, in AAA tissue, both mRNA and protein expressions of SM22α, α-SMA, β-tubulin and desmin were significantly decreased, especially that of SM22α, whereas the mRNA and protein expression levels of OPN were significantly increased (all P<0.05). Conclusion: There is decreased expression of SM22α and cytoskeletal protein level, and increased OPN level in AAA tissue, which may be closely associated with the occurrence of AAA.