The potato cell wall pectinase was isolated and purified by ammonium sulfate gradient precipitation with a combination of three phase partitioning method， and the effects of environmental conditions on the activity and enzymatic features of cell wall pectinase in potato were studied. The results showed that when the saturation of ammonium sulfate was 60%， pectinase reached the maximum precipitation point. Through a process of two three phase partitioning and purification， the specific activity of pectinase， the purification fold and the recovery rate reached 2 012.40 U/mg， 5.72 and 82%. The optimal temperature was 20 ℃ and the optimal pH was 4.8. Ca2+ and Cu2+ could significantly amp up pectinase activity， and Ca2+ possessed the strongest promoting effect on pectinase(251%)， while Zn2+ and Na+ had no effect on pectinase activity， Whereas K+ and Mg2+ had a significant inhibiting effect on pectinase activity. The enzymatic activity reached to the climax (4 667.10 U/g) when the reaction was conducted at the optimal temperature and pH for 40 min. The kinetic constants of pectinase were Km=0.13 mg/mL and Vmax=277.80 U/g. Simultaneousl enzymolysis effect the gelled potato pectin and the original pectin were compared. It turned out to be that gelled pectin was resistant to potato cell wall pectinase.