BACKGROUND: The socioeconomic burden of low back pain (LBP) is increasing, and two potential triggers of LBP (disc degeneration and paraspinal muscle fatty infiltration) have attracted significant attention in recent years. Previous studies have proposed that LBP is related to the morphology and composition of paraspinal muscles. However, the results remain conflicting and controversial. PURPOSE: This study aims to review and analyze the imaging findings of paraspinal muscle (Multifidus[MF], erector spinae [ES],psoas major[PM],quadratus lumborum[QL]) morphology (functional cross-sectional area[FCSA]=total cross-sectional area[TCSA]-fatty infiltration[FI]) and compositional alterations (FI) in individuals with and without LBP, to investigate the relationship between these changes and LBP, and to investigate the value of the morphology and composition of the paraspinal muscles in predicting pain and dysfunction in patients with LBP. METHODS: A comprehensive search of the PubMed, EMBASE, Cochrane and Web of Science databases was conducted to identify eligible studies up to 31st August 2024. This search was restricted to English-language articles investigating the association between the FCSA and FI of paraspinal muscle in people with LBP compared with a control group without LBP. A total of 2366 articles were identified, of which 50 met the inclusion and exclusion criteria. Literature quality was assessed using the Newcastle Ottawa Scale (NOS) and 17 of the eligible articles were included in the Meta-analysis. RESULTS: This meta-analysis included 17 studies investigating paraspinal muscle alterations in patients with low back pain (LBP). The pooled analysis revealed a significant reduction in the functional cross-sectional area (FCSA) of the multifidus muscle (SMD = -0.369, 95% CI = -0.581 to -0.156, P = 0.001), accompanied by increased fat infiltration in both the multifidus (SMD = 0.583, 95% CI = 0.259 to 0.908, P < 0.001) and erector spinae muscles (SMD = 0.235, 95% CI = 0.103 to 0.367, P = 0.001). No significant differences were observed in the FCSA of the erector spinae, psoas major, or quadratus lumborum muscles, nor in the fat infiltration of the psoas major. Subgroup analysis demonstrated a pronounced reduction in multifidus FCSA at the L level (SMD = -0.505, 95% CI = -0.722 to -0.287, P < 0.001), indicating significant muscle quality deterioration in LBP patients. CONCLUSION: The morphology and composition of the MF muscle are altered in individuals with LBP, characterized by reduced MF muscles, particularly at the L level, and increased FI compared to healthy controls. Additionally, a slight increase in fatty infiltration is observed in the erector spinae muscles of low back pain patients.