Abstract: Objective: To establish a preparation method of Atractylodes macrocephala Koidz polysaccharide (AMP) sulfate with anti-hyperplasia of mammary. Methods: AMP were sulfated by sulfated method, and the optimal conditions for the sulfated modification were determined by response surface methodology. The structures of AMP and SAMP were initially analyzed by infrared spectroscopy (IR) and High-Performance Gel Chromatography (HPGPC). The anti-oxidative activity in vitro of polysaccharide was investigated by testing the DPPH, ABTS⁺, OH free radical scavenging ability of AMP and SAMP. Rat model of mammary gland hyperplasia was established by intramuscular injection of estradiol benzoate and progesterone. The rats weight and breast diameter were recorded and the pathological organization form of mammary gland of rats were observed. Results: The optimum preparation conditions were as follows: Ratio of conditions of volume ratio of sulfuric acid and n-butanol 2:1, reaction temperature −4 ℃, reaction time 21 min. The degree of substitution of SAMP was 0.59±0.00391. The HPGPC results showed the relative molecular weights for AMP and SAMP were 2719 and 33524 Da, respectively. The IR spectra showed that SAMP had characteristic absorption peaks of S=O and C-O-S appeared near 833 and 1226 cm⁻¹, indicating that the sulfated was successful. When the sample concentration was 0.5 mg/mL, the DPPH, ABTS⁺, OH free radical scavenging activities of SAMP were 54.91% , 38.21%, and 42.23%, respectively. Compared with the model group, the diameter of the nipples of the rats in the SAMP group decreased (P<0.01), the number of acinars were decreased, the mammary gland hyperplasia was reduced and SAMP exhibits stronger anti MGH activity than AMP. Conclusion: The study indicated that the optimized processing technology of SAMP modified by response surface methodology was stable and feasible and the sulfated modification could increase the anti-MGH capacity of AMP.