Along　with　the　construction　of　many　coal-fired　power　plants,　the　supply　of　bituminous　coal　has　become　a　key　interest　in　China.　An　increasing　number　of　coal-fired　power　plants　consume　lignite.　However,　lignite-fired　power　plants　feature　a　very　low　plant　thermal　efficiency.　But　by　means　of　lignite　predrying,　the　efficiency　of　the　lignite-fired　power　system　can　be　improved,　and　the　recovery　of　waste　heat　from　the　dryer　can　improve　the　plant　thermal　efficiency　further.　In　the　present　article　a　theoretical　model　of　the　predried　lignite-fired　power　plant　with　the　waste　heat　recovery　system　based　on　basic　thermal　principles　is　developed　and　an　existing　case　is　analyzed.　The　above　plant　was　shown　to　enhance　the　thermal　efficiency　of　a　conventional　lignite-fired　power　plant　by　approximately　2.45%,　which　is　0.58%　higher　than　predried　lignite-fired　power　plant　without　waste　heat　recovery.　Moreover,　the　influence　of　system　parameters　on　the　improvement　of　the　plant　thermal　efficiency　is　determined.　The　results　can　be　used　in　optimization　of　a　waste　heat　recovery　system　in　the　thermodynamic　process　to　increase　the　economy　of　lignite-fired　power　plants.