On-surface synthesis never fails to fascinate chemists by producing new functional polymers which can hardly been prepared via traditional solution chemistry.Among those newly prepared polymers,graphene nanoribbons (GNRs),featured with tunable band gap,have attracted substantial attention because they are considered as promising candidates for next generation carbon-based semiconductors.Here,we summarize the recent advances of GNRs prepared on single crystal surfaces with emphasis on the structural tuning and electronic properties of GNRs.Moreover,critical developments toward the application of GNRs have also been reviewed including the mass fabrication and the performance of GNRs as field effect transistors.