To enhance the biological activity of Chuanminshen violaceum polysaccharides (CVPs), these polysaccharides were extracted using an ultrasonic-assisted enzymatic method and sulfated using the concentrated sulfuric acid method to produce sulfated CVPs (S-CVPs). The S-CVPs were then purified using DEAE-52 and Sephadex G-100 chromatography. Fourier-transform infrared spectroscopy revealed characteristic absorption bands of sulfate groups at 1 204 and 816 cm-1 in the purified S-CVPs. Scanning electron microscopy revealed striated gaps in the S-CVP structure, which could more readily bind water molecules. High-performance gel permeation chromatography and high-performance liquid chromatography analysis showed that the purified S-CVP fraction was a polysaccharide polymer with a molecular weight of 4.2 kDa, composed of 81.00% glucose, 5.31% galactose, 4.54% mannose, and 3.52% galacturonic acid. The in vitro antioxidant activity of the sulfated polysaccharides was assessed using DPPH, ABTS+, and OH radical scavenging assays. The antioxidant capacities of the fractions were ranked as follows: purified S-CVPs>SCVPs>CVPs. In summary, sulfation of CVPs significantly enhances their in vitro antioxidant activity. Furthermore, the high-purity polysaccharides obtained through isolation and purification showed enhanced antioxidant capacity. These findings provide a basis for the further development and utilization of C. violaceum.