Pectin was extracted from sweet potato residues.Sugar composition and degree of esterification(DE) of pectin were determined by high performance anion exchange chromatography and titration method respectively.Mi-crostructure of pectin powder and pectin gel was observed by scanning electron microscope.The effect of temperature,pH,shear rate and Ca2 + concentration on viscosity of pectin solution were also investigated.The results showed that The order of sugar composition in sweet potato pectin was galacturonic acid(79.23%) > galactose(9.48%) > rham-nose(7.38%) > glucuronic acid(3.76%) > xylose(3.74%) > glucose(1.47%) > arabinose(1.23%),DE was 31.71%.The microstructure of pectin powder was irregular flake-like,whereas the pectin gel had a porous network form.The viscosity of pectin solution decreased when the temperature was increasing;pH affected viscosity obviously,pectin solution had higher viscosity at the pH 5.0 and 9.0,and the value were 3.82mP.s and 3.65mP.s respec-tively.With increasing the shear rate,viscosity decreased rapidly,and then trended to steady;Ca2 + could improve the viscosity of pectin solution remarkably,in the extent of 0 ～ 50 mmol/L,there was positive relationship between Ca2 + concentration and viscosity of pectin solution.