Abstract: The fermented soybean curd from self-made(M1 and M2)and supermarket(C1 and C2) were used as raw materials, flavor substances of 4 kinds of fermented soybean curd were analyzed by qualitative and quantitative analysis by solid-phase microextraction and gas phase chromatography-mass spectrometry(SPME-GC-MS), and the main flavor substances were evaluated by combinging the aroma threshold and relative odor activity value(ROAV). The results showed that 74 flavor substances of 4 kinds of fermented soybean curd were detected. The ROAV showed such as ethanol, phenol, 1-methoxy-4-(1-propenyl)-benzene, caryophyllene, 2-methoxy-3-(2-propenyl)-phenol, methyl salicylate, benzenepropanoic acidmethyl ester, benzenepropanoic acidethyl ester, dihydro-5-pentyl-2(3H)-furanone, decanoic acidethyl ester, hexadecanoic acidethyl ester and ethyl oleate were the key flavor substances. The result of principal component analysis (PCA) for the key flavor compounds showed that 1-methoxy-4-(1-propenyl)-benzene was the most important contributor to the flavor of M1 and M2, and ethanol was the most important contributor to the flavor of C1 and C2. There had differences in the types and relative contents of main flavor substances of Sufu between homemade and market, which would be caused by the different raw materials and processing technology.