Pure　perovskite　phase　LNKN　nanopowders　with　mean　grain　size　of　30　nm　were　synthesized　via　an　economical　sol-gel　route　using　Nb2O5　as　Nb　source.　The　nanopowders　were　further　densified　using　the　conventional　sintering　process.　Compared　with　the　ceramic　densified　from　coarse　particles　in　normal　solid　phase　process,　the　sintered　ceramic　from　nanopowders　shows　more　disinct　abnormal　grain　growth　phenomenon.　The　origin　of　abnormal　grain　growth　can　be　attributed　to　the　liquid-phase　sintering　mechanism　in　local　area,　where　nanoparticles　present　high　sintering　ability.　This　work　has　important　guiding　significance　for　the　synthesis　of　other　functional　ceramic　containing　niobium　by　water-based　sol-gel　method,　and　it　provides　crucial　reference　value　for　the　study　of　sintering　and　densification　behavior　of　low　melting　point　volatile　nanopowder.