Microcapsule-based　self-healing　materials　have　attracted　overwhelming　attention　for　their　smart　damage　re-covery　capability　with　great　potential　applications　in　aerospace,　electronic　devices,　etc.　Numerous　experimental　and　numerical　methods　have　been　developed　to　analyze　the　healing　performance.　However,　there　is　a　lack　of　understanding　of　the　in-situ　damaging　and　healing　process　under　external　loading.　Here,　an　in-situ　investigation　on　the　internal　three-dimensional　microstructure　evolution　and　damaging-healing　process　of　a　dual　-microcapsule-based　self-healing　material　with　fast　healing　chemistry　was　performed　by　SR-CT　technology.　Some　important　but　previously　undiscovered　phenomena　such　as　microcapsules　rupture,　crack　propagation,　healing　liquids　flowing　and　mixing　were　clearly　observed.　Further　study　combined　with　3-Dimensional　stress　field　analysis　indicates　that　the　healing　behaviors　have　significant　regional　characteristics,　and　were　affected　by　multiple　factors　including　the　geometric,　internal　defects　and　especially　the　gradient　distribution　of　stress　field.　These　results　may　provide　useful　guidance　for　the　design　and　performance　optimization　of　self-healing　materials.