In　the　present　work,　we　study　the　thermoelectric　properties　of　a　double　quantum　dots　serially　coupled　to　Luttinger　liquid　leads　considering　the　intralead　Coulomb　interaction.　We　explore　the　interplay　of　the　quantum　interference　effects　and　Coulomb　interaction　on　the　thermoelectric　efficiency　in　the　linear　and　nonlinear　regimes.　Numerical　results　demonstrate　that　in　the　linear　region,　the　enhanced　intralead　Coulomb　interactions　can　simultaneously　boost　power　factor　and　reduce　thermal　conductance.　Complete　destructive　quantum　interference　induced　by　the　Coulomb　interaction　generates　molecular　insulating　states,　achieving　a　remarkable　increase　of　the　figure　of　merit　ZT　up　to　650.　In　particular,　the　coexistence　of　Fano　resonance　and　destructive　interference　leads　to　a　huge　ZT　value　exceeding　2000.　In　the　nonlinear　region,　it　is　shown　that　the　efficiency　monotonically　increases　with　the　enhancement　of　the　intralead　Coulomb　interaction.　The　efficiency　at　maximum　power　comparable　to　the　Curzon-Ahlborn　efficiency　is　achieved.　However,　the　improvement　of　power　output　depends　on　both　Coulomb　interaction　and　dot-lead　coupling.　These　findings　provide　theoretical　guidelines　for　designing　coherent　nanoscale　thermoelectric　devices.