Abstract: In order to analyze the differences in volatile components between the mature green and mature yellow fruits of 3 kinds of red flesh guava, gas chromatography-ion mobility spectrometry (GC-IMS) was used to detect the volatile components in mature green and mature yellow of 3 kinds of red flesh guava. The results showed that 121 and 133 volatile components, including esters, aldehydes, alcohols, and ketones, were detected in mature green and mature yellow of 3 kinds of red flesh guava. Hexanal (monomer and dimer), 2-hexenal, ethyl trans-2-butenoate, acetic acid ethyl ester (dimer), (Z)-3-hexen-1-ol (dimer), 1-penten-3-one (dimer) and (E)-2-pentenal (dimer) as the key aroma compounds of 3 kinds of red flesh guava. Terpene compounds such as beta-ocimene, gamma-terpinene and 1.8-cineole were also revealed as important aroma constituents. The volatile components of the 3 red flesh guava differ greatly, especially the difference between ‘Xiguahong’ and the other 2 varieties was the largest. (Z)-3-hexenyl acetate (dimer), n-propyl acetate (dimer), 2-methyl-2-propanol, benzyl alcohol, and octanal (dimer) were the characteristic volatile components of ‘Xiguahong’. The peak volumes of 44 main volatile components were analyzed, it was found that the content of most volatile components, such as gamma-terpinene, 1,8-cineole (monomer), (E)-2-pentenal (dimer), 1-penten-3-one (dimer), and acetic acid ethyl ester (dimer), significantly increased during fruit ripening of the 3 kinds of guava, while the content of a few volatile components, such as beta-ocimene (monomer) and methyl-5-hepten-2-one were significantly decreased.