【】Objective To investigate the protective effect and mechanism of Polygonatum sibiricum Polysaccharides (PSP) on Diabetic cardiomyopathies (DCM). Methods Forty SPF-grade male SD rats were randomly divided into normal group, model group, PSP group and metformin group. After four weeks of high-fat feeding, streptozotocin (STZ) was intraperitoneally injected to establish diabetes mellitus animal model, and the drug was administered by gavage for 12 weeks, and the body weights and blood glucose were recorded every fortnight. At the 16th week, cardiac function was detected by non-invasive echocardiography; myocardial histopathological changes and the degree of myocardial fibrosis were assessed by HE and Masson staining; serum interleukin-6 (interleukin-6,IL-6), interleukin-1β (interleukin-1β,IL-1β), Interleukin-18 (IL-18), tumour necrosis factor-α (TNF-α), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were detected by enzyme-linked immunosorbent assay (ELISA); The expression levels of fibrosis-related proteins TGF-β1, Smad2, Collagen-Ⅰ, Collagen-Ⅲ and pyroptosis-related proteins NLRP3, ASC and Caspase-1 were detected in rat myocardial tissues by protein immunoblotting (Western blot). Cellular experiments were performed by exposing H9c2 cells to high glucose (40 mmol/L) to mimic the in vitro DCM model, and cell viability was detected by CCK-8 assay; apoptotic cell ratio was detected by flow cytometry. Results Compared with the model group, rats in the treatment group had significantly lower blood glucose, lipid, and serum inflammatory factor levels (P < 0.05), significantly higher Ejection fraction(EF% )and fractional shortening(FS%) values (P < 0.05), and improved cardiac function; myocardial fibers were better aligned, and collagen fiber accumulation was reduced; and myocardial tissues of NLRP3, ASC, Caspase-1, Collagen-Ⅰ, Collagen-III, TGF-β1 and Smad2 protein expression levels were significantly reduced (P < 0.05). In the cellular assay the PSP treatment group increased the viability and decreased the proportion of apoptotic cells in high glucose-induced H9c2 cardiomyocytes. Conclusion PSP can improve glucose-lipid metabolism, protect cardiac function, and delay the occurrence of myocardial fibrosis in diabetic rats, and it can also improve the viability of cardiomyocytes, and its mechanism of action may be related to the inhibition of cellular pyroptosis and delay the occurrence of ventricular remodeling.