Abstract: The technical parameters for extracting polysaccharide from Wedelia prostrate with ultrasonic technique were optimized by orthogonal experiments,the effects of the extracted polysaccharide on the moisture retentivity of cut tobacco and the sensory pleasurableness of cigarette were studied.The results indicated that: 1) The number of extraction repetition was the major factor influencing extraction yield,followed by ultrasonic power,solid-liquid ratio and extraction time.2) The optimal extraction conditions were:extraction twice,30 minutes per extraction cycle,ultrasonic power 360 W,and solid-liquid ratio 1:20.3) The moisture retentivity of polysaccharide sample was significantly higher than that of propylene glycol in 12 hours,which indicated that the polysaccharide from Wedelia prostrate could reduce moisture dissipation.After storing at low humidity for a long period,the reduction of moisture content in cut tobacco added with 5% polysaccharide was 18.28% less than that added with 5% propylene glycol.The polysaccharide from Wedelia prostrate could effectively improve the moisture retentivity of cut tobacco and reduce the moisture dissipation of cigarette.