In order to explore the aroma difference between green pepper and red pepper and analyze the reasons for the difference, in this paper, the volatile components of green and red pepper were extracted by solvent-assisted flavor evaporation (SAFE), at the same time, gas chromatography-mass spectrometry (GC-MS) was used to analyse the samples qualitatively and quantitatively. In addition, aroma extract dilution analysis (AEDA) united with gas chromatography-olfactometry (GC-O) was used to analyze the key flavor substances of different pepper. Furthermore, the odor activity values (OAVs) were calculated to determine the relative contribution of each compound to the odor of different pepper. Depending on the result of analysis, the key aroma active substances of green pepper are linaool, β-phellandrene, myrcene, eucalyptol, D-limonene and sabinene. In the meanwhile, the key aroma active substances of red pepper are linalool, myrcene, eucalyptol, D-limonene and sabinene. The main reasons for the aroma differences may be that green pepper consists of more kinds of alkene, alcohols, aldehydes, ethers. However, red pepper contains more types of ketones and esters. Moreover, linalool, myrcene and eucalyptol have different contributions to the overall aroma of green and red pepper. The results of this experiment contribute to identify the components of pepper and distinguish the categories of pepper.