Guided　waves　have　been　utilized　in　various　manners　for　non-destructive　evaluation　and　testing.　Due　to　the　dispersive　and　multi-mode　characteristics　of　guided　waves,　the　pulse　of　energy　will　spread　out　in　space　and　time　as　it　propagates.　For　long-range　guided　waves　inspection　application,　it　constrains　the　choice　of　operating　point　to　regions　on　the　dispersion　curves　where　dispersion　effect　is　relatively　small.　Based　on　the　knowledge　of　the　guided　waves　propagation　in　time-space,　a　space　model　is　established　to　compensate　the　dispersion　in　long　range　guided　wave　testing.　Consequently,　the　characteristics　of　structure,　such　as　the　length　of　structure　or　the　position　of　defect,　can　be　obtained　directly,　and　the　resolution　of　detection　can　be　improved.　It　is　shown　that　the　technique　can　improve　and　extend　the　effect　of　guided　waves　for　NDT　methods.