Current　web　services　standards　lack　the　support　of　formal　semantic　descriptions　of　a　service＇s　nonfunctional　characters,　i.e.　its　Quality　Of　Service.　When　a　large　number　of　functionally-equivalent　services　have　been　discovered,　it　is　difficult　for　users　to　choose　which　one　to　be　invoked.　Thus,　QoS　becomes　a　very　critical　factor　in　selecting　among　these　candidates　services　to　best　meet　users　needs.　In　this　paper,　we　design　and　build　a　general　QoS　ontology　to　support　web　services　nonfunctional　features.　This　ontology　can　solve　the　interoperability　of　QoS　description.　We　also　give　a　semantic　web　services　discovery　framework　based　on　QoS　ontology.　The　framework　supports　the　automatic　discovery　of　web　services　and　it　can　improve　the　efficiency　for　users　to　find　the　best　services.　©　2010　IEEE.