Lignite,　a　kind　of　low　rank　coal,　has　the　characteristics　of　high　moisture,　high　volatile,　high　ash　and　low　heat　value.　The　low-temperature　pyrolysis　technology　is　potential　to　improve　the　utilization　efficiency　of　lignite.　Therefore,　a　lignite-based　energy　system　integrated　with　pre-drying　and　low-temperature　pyrolysis　was　proposed　in　this　paper.　To　assess　the　influence　of　pre-drying　process,　theoretical　models　were　developed　based　on　thermodynamics,　and　a　case　analysis　was　then　performed　to　get　the　quantitative　effect　of　pre-drying　on　efficiency　of　energy　utilization.　Results　show　that　pre-drying　on　PPPS　theoretical　model　can　significantly　improve　the　utilization　of　lignite　by　1.46%.