The　development　of　new　routes　for　the　production　of　thermoelectric　materials　with　low-cost　and　high-performance　characteristics　has　been　one　of　the　long-term　strategies　for　saving　and　harvesting　thermal　energy.　Herein,　we　report　a　new　approach　for　improving　thermoelectric　properties　by　employing　the　intrinsically　low　thermal　conductivity　of　a　quasi-one-dimensional　(quasi-1D)　crystal　structure　and　optimizing　the　power　factor　with　aliovalent　ion　doping.　As　an　example,　we　demonstrated　that　SbCrSe3,　in　which　two　parallel　chains　of　CrSe6　octahedra　are　linked　by　antimony　atoms,　possesses　a　quasi-1D　property　that　resulted　in　an　ultra-low　thermal　conductivity　of　0.56　W　m(-1)　K-1　at　900　K.　After　maximizing　the　power　factor　by　Pb　doping,　the　peak　ZT　value　of　the　optimized　Pb-doped　sample　reached　0.46　at　900　K,　which　is　an　enhancement　of　24　times　that　of　the　parent　SbCrSe3　structure.　The　mechanisms　that　lead　to　low　thermal　conductivity　derive　from　anharmonic　phonons　with　the　presence　of　the　lone-pair　electrons　of　Sb　atoms　and　weak　bonds　between　the　CrSe6　double　chains.　These　results　shed　new　light　on　the　design　of　new　and　high-performance　thermoelectric　materials.