The effects of 3 kinds of pretreatment, acid hydrolyzation, enzymatic hydrolyzation and acidification enzymatic hydrolyzation, on the detection of the content of premna microphylla leaves pectin by ion chromatography were studied. The esterification of galacturonic acid with different amount of acidic solution was also studied. 26% galacturonic acid was remained after reacting in 2 mol/L HCl for 12 h. The result was a little low by acid hydrolyzation with 2 mol/L HCl. The pectin accounting for 1.06%~3.78% of the total weight of the leaves was remained without being hydrolyzed after enzymatic hydrolysis with 400 mg pectinase for 4 h. The leaves were acidified with 0.05 mol/L HCl, and the dilute acid extract liquid and the residues were enzymatic hydrolyzed with 10 mg pectinase respectively. The result using acidification enzymatic hydrolyzation was 29.34% higher than that using the acid hydrolyzation, and 12.45% higher than that using the enzymatic hydrolysis, without esterification and with less amount of pectinase. The ion chromatography had good linearity with a correlation coefficient of 1.000 0, while the detection limit for galacturonic acid was 4.05 μg/L. The recovery of pectin in different premna microphylla leaves was above 95%, and the relative standard deviation (RSD) was less than 5%.