In order to determine the biosynthesis of garlic greening,the contents of citric acid,α-ketoglutarate,fumarate and δ-ALA were investigated.The results showed that with the storage time prolonged,the contents of citric acid,α-ketoglutarate,fumarate and ALA increased significantly,the strength of garlic greening was with the same trend.Treatment with Ca2 + could increase the content of citric acid,α-ketoglutarate and the strength of garlic greening,but decrease the content of fumarate significantly.Malonic acid can reduce the content of fumarate significantly,the garlic greening rate increased first and then decreased slightly.It showed that tricarboxylic acid cycle and biosynthesis of garlic green pigment was correlated.