The　ancient　buildings　has　been　exposing　to　natural　environment　for　many　years,　and　most　of　them　are　suffered　from　damages　by　wind,　sunlight　and　rain,　resulting　in　destruction　with　various　degrees.　The　research　on　restoration　materials　of　ancient　building　has　always　been　the　focus　for　cultural　relic　conservation.　As　one　of　the　earliest　type　of　inorganic　cementitious　materials　used　by　human　beings,　lime　features　moderate　mechanical　strength,　favorable　permeability　and　breathability,　satisfactory　compatibility　with　ancient　buildings,　and　cause　no　secondary　damage　to　ancient　buildings,　showing　an　irreplaceable　advantage　in　the　field　of　restoration　of　ancient　buildings.　Nevertheless,　there　are　still　some　problems　in　the　lime-based　mortars,　especially　the　low　early　strength　and　poor　durability,　which　severely　hinders　their　widespread　application.　As　an　air-hardening　material,　lime　is　hardened　by　gradual　crystallization　and　carbonation　in　air,　presenting　a　slow　growth　of　its　strength.　Besides,　lime　will　lose　a　large　amount　of　free　water　in　the　process　of　drying　and　hardening,　forming　a　porous　structure,　providing　a　channel　for　water　and　some　soluble　ions　to　enter　into　the　slurry,　which　adversely　affecting　its　frost　resistance　and　erosion　resis-tance.　In　recent　years,　scholars　have　optimized　the　composition　of　lime　mortar,　and　obtained　lime-based　mortars　with　significantly　improved　pro-perties.　Generally,　lime-based　mortars　include　lime　mortars,　natural　hydraulic　lime　mortars,　lime-cement　mortars　and　lime-pozzolan　mortars.　Lime　mortars　holds　best　compatibility　with　ancient　buildings,　but　the　low　early　strength　block　their　application.　The　recent　research　work　concentrate　on　the　impact　of　the　lime　sand　ratio　and　additives　on　the　pore　structure　and　mechanical　properties　of　lime　mortar.　Natural　hydraulic　lime　contained　a　certain　amount　of　hydraulic　component　dicalcium　silicate　show　superiority　in　early　strength　compared　with　lime.　The　related　research　of　natural　hydraulic　lime　started　late　in　China.　Although　natural　hydrated　lime　with　different　strength　grades　have　been　successfully　prepared　in　laboratory,　the　preparation　process　is　not　yet　mature.　It　has　been　reported　that　a　suitable　amount　of　auxiliary　cementing　materials　have　been　introduced　into　natural　hydrated　lime　and　excellent　repairing　mortar　has　obtained　in　the　research　by　foreign　scholars.　Lime-cement　mortars　come　from　a　wide　range　of　sources　and　have　similar　pore　structure　and　performance　with　natural　hydraulic　lime　mortars.　However,　the　compatibility　between　lime-cement　mortars　and　the　base　materials　of　ancient　buildings　still　remain　controversial.　The　early　strength　of　lime-pozzolan　mortars　is　mainly　derived　from　the　volcanic　ash　reaction　between　calcium　hydroxide　and　pozzolanic　materials,　and　pozzolanic　reaction　is　closely　related　to　the　pozzolanic　activity　and　curing　conditions.　In　this　paper,　we　introduce　the　merits,　drawbacks　and　application　situation　of　the　four　kind　of　limed-based　restoration　mortars,　describe　the　relationship　between　the　structure　and　properties　of　lime-based　mortars.　According　to　the　compatibility　requirements　of　ancient　buildings　restoration,　we　point　out　the　problems　of　lime-based　mortars,　and　then　make　recommendations　for　further　research　work.　©　2019,　Materials　Review　Magazine.　All　right　reserved.