Abstract: After the compound enzymatic hydrolysis of Biluochun tea powder, the ultrasonic-assisted extraction process of Biluochun polysaccharide (BTP) was optimized by response surface experiment. The anion column and gel column were used for separation and purification. The physicochemical composition, functional group composition, relative molecular mass and molecular conformation of each component were determined by Fourier transform infrared spectroscopy (FT-IR), ultraviolet spectrum scanning and high performance volume exclusion chromatography (HPSEC). The experiments showed that the best extraction process was ultrasonic power 200 W, ultrasonic temperature 45 ℃, material-to-liquid ratio 40:1 mL/g, ultrasonic time 35 min, and the yield of Biluochun polysaccharides was 26.74%. BTPA1 was obtained from BTP by DEAE-Sepharose anion exchange column chromatography, and BTPA1 was separated by Sepharose CL-6B gel column chromatography to obtain BTPA11 and BTPA12. The neutral sugar content of BTP, BTPA1, BTPA11 and BTPA12 were 59.39%, 66.86%, 77.43% and 62.61%, and the uronic acid content was 51.06%, 53.53%, 54.45% and 65.39%, respectively. After spectral and relative molecular mass analysis, the four Biluochun polysaccharide components all contained acid sugars and pyran ring structures; BTPA11 and BTPA12 were polysaccharides with uniform relative molecular mass distribution, and their relative molecular masses were 1604.2 kDa and 353.7 kDa; The slopes of the configuration of BTPA11 and BTPA12 were 0.12 and 0.15, and both might be high-branched spherical structures. The ultrasound-assisted enzyme extraction of Biluochun polysaccharide had a higher yield, and the analysis of the properties of each component would facilitate the study of fine structure and the development and utilization of active functions.