Four potato pectin polysaccharides were extracted from potato residue which had been adopted the enzymatic removal of starch and protein by hydrochloric acid solution , citric acid solution, alkaline phosphate solution and compound salt solution respectively; furthermore, ultra-filtrated, precipitate by ethanol and lyophilized. Effect of different extraction methods on yield, the composition characters of potato pectic polysaccharide were researched. The results show that the bigger extraction yield, produced by alkaline phosphate and compound salt extraction ,were 29.89% and 21.01% , respectively. The bigger galacturonic acid content of pectic polysaccharide that was used alkaline phosphate solution and compound salt solution were 29.71% and 31.57% , respectively. The ash content of pectic polysaccharide that was used alkaline phosphate solution (22.38%) is significantly higher than other three kinds of one (2.09%-2.48%). Pectic polysaccharide extracted by four kinds of processing methods was of low-methoxyl pectin. There was no significant difference between protein content of four kinds of pectic polysaccharide (less than 3.0%).Galactose was the major neutral monosaccharide units along with a small portion of arabinose, rhamnose and glucose. The molecular weights (Mp) of four pectic polysaccharide that was hetetopolysaccharide ranged from 1.65×104u to 1.17×106u.The infrared spectra showed that all pectins extracted from potato had typical functional groups of pectin. The research has theoretical and practical significance of development and production of potato pectin.