A rapid and new specific colorimetric method of pectin with carbazole-sulfuric acid is established. The procedure is as follows: A test tube containing 0.5 ml of pectin solution (5 to 80 μg) is placed in an ice bath, six ml of a cold mixture of 1 part of water and 7 parts of concentrated sulfuric acid of special grade are pipetted into the tube and mixed, then, 0.2 ml of 0.1% alcoholic carbazole is added to the mixture in the ice bath. After shaken vigorously, the test tube is immersed in a water bath at 75℃ for 20 minutes and cooled in running tap water. A red color is estimated at 525 mμ with a spectrophotometer. It is proper that the colorimetry is available for estimation of pectic acid and D-galacturonic acid.