Aging　is　an　essential　operation　to　perfect　the　flavor　quality　of　Hungjiu.　In　this　study,　formation　mechanism　of　flavor　compounds　responsible　for　the　characteristic　flavor　of　aged　Huangjiu　was　investigated.　The　contents　of　umami　and　bitter　free　amino　acids　(FAA)　increased　with　the　storage　period　prolonged,　while　that　of　sweet　FAA　showed　downward　trend.　Gas　chromatograph-mass　spectrometry　and　principal　component　analysis　indicated　that　the　volatile　flavor　compounds　with　OAV　exceed　1,　especially　middle-chain　fatty-acid-ethyl-esters　and　aromatic　compounds,　dominated　the　characteristic　flavor　of　aged　Huangjiu.　Low　field-NMR　was　firstly　applied　to　characterize　the　molecular　association　between　water　and　dissolved　flavor　compounds　in　aged　Huangjiu.　The　results　showed　that　basic　amino　acids　contributed　greatly　to　the　flavor　formation　of　aged　Huangjiu　via　molecular　association.　In　addition,　the　molecular　association　significantly　promoted　the　accumulation　of　flavor　compounds　with　OAV　＞　1,　especially　ethyl　esters.