[Objective] This study aimed to analyze the differences in volatile compounds between the mature green and mature yellow fruits of guava. [Methods] The volatile compounds in 4 kinds of guava fruits during the mature green and mature yellow were detected by gas chromatography ion mobility spectroscopy (GC-IMS). [Results] 130 volatile compounds were detected in 4 kinds of guava fruits ("Yanzhihong", "Sijihong", "Baizhenzhu" and "Siji"). Qualitative analysis showed that the fruit flavored ethyl trans-2-butenate, the grass flavored 2-hexenal and hexanal were the volatile compounds with the highest content among the 4 kinds of guava fruits. The content of volatile components in the mature green and mature yellow fruits of "Baizhenzhu" showed the largest changes, while the content of volatile components in the mature green and mature yellow fruits of "Siji" showed the smallest changes. Compared with the mature green fruits, (E)-2-hexenyl acetate and acetic acid ethyl ester (dimer) showed a significant increase in content in the mature yellow fruits of "Siji", while only alpha-Pinene (monomer) showed a significant decrease. [Conclusion] There are significant differences in volatile components during the mature green fruits of 4 kinds of guava. The volatile components of "Yanzhihong" and "Sijihong" during mature yellow fruits were very similar, but they had significant differences from "Baizhenzhu" and "Siji".