Abstract:The monoterpenes in white bitter gourd （K1），white green bitter gourd （K2），yellow-green bitter gourd （K3），light green bitter gourd （K4）and green bitter gourd （K5）were qualitatively and quantitatively analyzed by head space solid-phase micro-extractions （HS-SPME）combined with gas chromatography-mass spectrometry （GC-MS）.The results showed that 5 different fruit color bitter gourd fruits were detected 29 kinds of monoterpene ingredients，included 11 monoterpene alcohols，9 monononanals，4 monoterpenes，3 monoterpenoids，1 monoterpene ester and 1 monodecyne.The total content of monoterpenoids in white-green bitter gourd （K2）was the highest，accounting for 75.387 % of total volatile matter.The total content of light green balsam was the lowest，accounting for 55.57%of the total volatile matter.It was detected that the content of myrtenol in the volatiles of bitter gourd fruit was the highest，exceeding 40 % of the total volatile matter.It was speculated that myrtenol was a characteristic aroma substance of bitter gourd fruit.Principal component analysis was carried out for 28 monoterpene components other than myrtenol：the monoterpenoids could be divided into two principal components，and the cumulative variance contribution rate reached 83.073 %，and the first principal component representative variables were：cis-sterol，β -cyclocitral，geranial，thujone，geraniol，α-Ionone；representative variables of the second principal component were：L-perillin，trans-4，5-diepoxy（E）-2-nonenal，cis-4，5-diepoxy（E）-2-nonenal，1α，2α，5α-2-methyl-5-（1-methylethenyl）cyclopentanecarboxaldehyde，β-ionone.Cluster analysis could divide five different fruit bitter gourds into two categories.The first category was：white bitter gourd（K1），white green bitter gourd（K2），yellow green bitter gourd （K3）；the second type was：light green bitter gourd （K4）and green bitter gourd （K5），the monoterpenoids in the same kind of bitter gourd fruit had higher similarity in composition and content.