Abstract: The volatile and non-volatile flavor composition are important indicators to evaluate the quality of mushroom. In order to explore the composition and relative content of flavor compounds in 5 fresh mushrooms, the flavor components were investigated and classified using high performance liquid chromatography (HPLC), headspace solid-phase micro-extraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), and the contribution of different components to the whole volatile was studied by the relative odor activity value (ROAV). The results showed that 35 volatile compounds were identified in 5 fresh mushrooms, including 5 aldehydes, 5 ketones, 9 alcohols, 8 alkanes, 6 heterocycles and sulfides, 1 esters and 1 nitrogen-containing compounds. Among the obtained compounds, 8 volatile ingredients including benzaldehyde, 3-octanone, 1-octen-3-one, 3-octanol, 2-ethyl-1-hexanol, 2-acetyl-5-methylfuran, 2-pentylfuran and methoxy-phenyl-oxime were detected in all the species. The key volatile aroma components of Pleurotus ostreatus were 1-octen-3-one, 1-octen-3-ol and 3-octanone, and those of Lentinus edodes were dimethyl disulfide, dimethyl trisulfide, 1-octen-3-one and methanethiol. 1-octen-3-one, 3-octanone and 3-octanol were the key volatile aroma components of Agaricus bisporus and Flammulina velutipes while 1-octen-3-one and 1-octen-3-ol were the key volatile aroma components of Pleurotus eryngii. The content of total free amino acid in 5 fresh mushrooms was 2.72~3.65 mg/g, the content of flavor 5'-nucleotides was 154.40~1013.60 μg/g and the contents of which were significantly difference.This study helped to understand the flavor characteristics of edible mushroom and provide guidance for breed improvement, directive breeding and the processing of edible mushroom.