To establish a polysaccharide-based quality control method for Salvia miltiorrhiza Radix Et Rhizoma (SMR), and to study the cardioprotective activity of Salvia miltiorrhiza polysaccharides (DSP). DSP samples were isolated from 60 different batches of SMR using hot water leaching and their physicochemical properties and structures were analyzed. Multiple DSP fingerprints were established, and zebrafish embryo experiments were designed. The DSP content ranged from 1.68 %-4.06 % as determined by the phenol-sulfuric acid method and high-performance liquid chromatography monosaccharide summation. The molecular weight distribution of DSP was analyzed using molecular weight fingerprints as A: 1.302-2.380 × 106 Da, B: 1.694-6.786 × 104 Da, C: 2.000 × 103-3.000 × 103, and D: 1.000 × 103-2.000 × 103. Infrared spectral fingerprints showed nine infrared absorption peaks (3373.47 cm-1, 2940.35 cm-1, 1738.69 cm-1, 1639.69 cm-1, 1434.33 cm-1, 1321.37 cm-1, 1253.52 cm-1, 1097.26 cm-1 and 1019.30 cm-1). Fingerprinting of the monosaccharide DSP components was carried out. The monosaccharide components of DSP were mannose, ribose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose. The experimental results obtained from studies on zebrafish embryos indicated that DSP could ameliorate pericardial edema and arrhythmia, which are consequences of cardiac injury. DSP exhibited the ability to mitigate alterations in the venous sinus-arterial bulb distance induced by cardiac injury. In this study, a polysaccharide-based quality control standard for SMR was established by determining the DSP content range, and molecular weights, identifying the characteristic peaks of functional groups, analyzing the monosaccharide composition, and generating fingerprints. This standard was developed to ensure the stability and consistency of SMR based on polysaccharides. The results of the zebrafish embryo experiments indicated that DSP exerted a beneficial impact on treating heart damage disease.