The changes of volatile flavor compounds in three varieties of sweet corn, “Zhongtian 9”, “Zhuyutian 8” and “Zhuyutian 1”, were investigated during the ripening process. The volatile flavor compounds were identified by headspace solid phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS) through NIST14 mass spectral database searching and retention index analysis as well as by gas chromatography-olfactory (GC-O), and were quantified by the internal standard method, in order to construct a volatile flavor profile and evaluate the aroma characteristics of sweet corn. The results showed that 61 volatile flavor compounds were detected across the three varieties during the ripening process. Maturity had significant effects on the type and content of volatile flavor compounds in sweet corn. The contents of ethyl nonylate, 1-heptanol and 1-hexanol significantly decreased with increasing maturity, while the contents of styrene, toluene, ethylbenzene and m-xylene significantly increased. Arenes were mainly accumulated in sweet corn during the maturation process. In terms of odor characteristics, the intensity of fatty aroma increased obviously with maturity, while the intensity of grassy aroma decreased obviously. There were significant differences among varieties in the composition and content of volatile flavor compounds. The number and amount of volatile flavor compounds in “Zhongtian 9” were significantly greater than those in the other two varieties at maturity, and the overall flavor intensity was the highest.