Abstract: The natural pigment was extracted from chestnut shell by alcohol-water as solvent assisted by microwave irradiation. The influence of extracting factors on extraction effect was studied using orthogonal test table L₉ (3⁴). The result indicates that the optimal extraction condition for chestnut shell pigment is respectively: microwave irradiation time 13 min, at75℃, volume fraction of ethanol solution 40%, and the mass ratio between solid and solvent 1:20 ( g:mL ). The yield is 7.02%. According to qualitative and stability tests, this pigment is a kind of flavonoid pigment which has good stabilities against light, reducing agent and oxidative agents.

Key words: chestnut shell, microwave irradiation, natural pigment