Lignite　pre-drying　can　improve　lignite-fired　power　system　efficiency　obviously,　and　the　waste　heat　recovery　can　improve　efficiency　further.　In　order　to　consider　the　effect　of　waste　heat　recovery　on　the　system　thermal　efficiency,　this　paper　established　the　thermal　equilibrium　model　of　the　dryer　and　the　theoretical　analysis　model　of　waste　heat　recovery　with　the　application　of　equivalent　heat　drop　method.　The　energy　saving　potential　with　waste　heat　recovery　was　analyzed　on　an　existing　600　MW　lignite-fired　power　plant,　and　the　influence　of　dryer　efficiency,　coal　preheater　efficiency　and　water　heater　efficiency　on　system　efficiency　improvement　were　calculated.　The　results　show　that:　coal　consumption　rate　reduction　of　pre-dried　lignite-fired　power　system　improves　from　11.44　g/(kW·h)　to　14.65　g/(kW·h)　with　waste　heat　recovery;　the　dryer　efficiency　is　the　most　obvious　factor　on　system　efficiency,　and　when　10%　higher　dryer　efficiency　is　improved　the　coal　consumption　rate　can　increase　1.8　g/(kW·h).　©　2012　Chin.　Soc.　for　Elec.　Eng.