The　narrowband　terahertz　(THz)　generation　on　lithium　niobate　(LN)　crystals　with　non-periodically　poled　domain　structures　was　demonstrated.　To　realize　THz　pulse　shaping,　the　optimal　domain　structures　were　designed　by　uing　simulated　annealing　(SA)　algorithm,　for　arbitrary　preset　frequency　components　and　intensities　of　THz　radiation　generation.　It　was　demonstrated　that　this　method　is　feasible　in　THz　pulse　shaping.