This study aimed to investigate the therapeutic effects and mechanisms of Apocynum venetum polysaccharide (AVP) on high-fat diet-induced metabolic associated fatty liver disease (MAFLD). Forty male C57BL/6 mice aged 6-8 weeks were randomly divided into four groups: normal group, model group, high-dose AVP group (400 mg/kg), and low-dose AVP group (200 mg/kg). A MAFLD model was established using a high-fat diet, followed by 12 weeks of intervention. Serum biochemical indicators, liver tissue injury, oxidative stress, lipid content, and inflammatory cytokine levels were measured. Hepatic pathological changes were observed through HE staining and Oil Red O staining, while 16S rRNA gene sequencing was employed to analyze gut microbiota in fecal samples. The results demonstrated that AVP significantly improved liver function parameters by reducing serum transaminase levels and elevating albumin levels (P<0.01 or P<0.05). AVP intervention also effectively ameliorated dyslipidemia. Histopathological examination revealed that AVP alleviated hepatic steatosis, inflammatory cell infiltration, and hepatocyte swelling, thereby mitigating liver inflammation (P<0.01 or P<0.05). 16S rRNA sequencing analysis indicated that AVP intervention notably increased the abundance of beneficial bacteria such as Bifidobacterium and Lactobacillus, while reducing pro-inflammatory bacteria like Enterococcus (P<0.01 or P<0.05). Furthermore, AVP restored the diversity and abundance of gut microbiota. In conclusion, AVP ameliorates MAFLD progression by modulating gut microbiota structure, providing novel insights for utilizing natural plant polysaccharides in MAFLD treatment.