Lignite　is　a　type　of　low-rank　coal,　which　is　uneconomically　transported　over　long　distances　and　does　not　efficiently　generate　electricity.　As　a　result,　lignite　utilization　and　application　is　very　limited;　lignite　is　mainly　used　as　a　low-level　fuel　that　generates　electricity　inefficiently　and　can　be　distributed　only　in　areas　near　lignite　mines.　With　increasing　requirements　in　efficiency　and　environmental　protection,　studying　a　new　lignite-fired　power　system　to　improve　the　efficiency　of　direct　lignite-fired　power　plants　is　very　important.　A　rotary-tube　dryer　is　mature　drying　equipment　used　in　a　pre-dried　lignite-fired　power　system　(PLPS).　However,　a　comprehensive　model　approach　on　the　influence　of　PLPS　parameters　on　power　generation　efficiency　and　optimization　has　not　been　previously　investigated.　In　the　current　paper,　a　PLPS　theoretical　model　was　developed　based　on　basic　thermal　principles,　and　a　case　analysis　was　performed　using　this　model　as　the　theoretical　foundation.　Parameter　influence　was　also　calculated　and　analyzed.　Results　show　that　the　PLPS　theoretical　model　can　evidently　increase　the　efficiency　of　a　conventional　lignite-fired　power　system　(CLPS)　by　approximately　1.87%　when　the　condensate　is　sent　to　the　de-aerator,　and　by　1.72%　when　the　condensate　is　sent　to　the　condenser　at　the　calculation　benchmark　condition　listed　in　this　paper.