In　this　paper,　accumulated　crystallization　of　amorphous　Ge2Sb2Te5　(a-GST)　films　induced　by　a　multi-pulsed　nanosecond　(ns)　excimer　laser　was　investigated　by　x-ray　diffraction　(XRD),　atomic　force　microscopy,　field-emission　scanning　electron　microscopy,　x-ray　photoelectron　spectroscopy　(XPS)　and　a　spectrophotometer.　XRD　analyses　revealed　that　detectable　crystallization　was　firstly　observed　in　the　preferred　orientation　(200),　followed　by　the　orientations　(220)　and　(111)　after　two　pulses.　Optical　contrast,　determined　by　crystallinity　as　well　as　surface　roughness,　was　found　to　retain　a　linear　relation　within　the　first　three　pulses.　A　layered　growth　mechanism　from　the　top　surface　to　the　interior　of　a-GST　films　was　used　to　explain　the　crystallization　behavior　induced　by　the　multi-pulse　ns　laser.　XPS　analyses　for　bond　rearrangement　and　electronic　structure　further　suggested　that　the　crystallization　process　was　performed　by　generating　new　bonds　of　Ge-Te　and　Sb-Te　after　laser　irradiations.　This　paper　presents　the　potential　of　multi-level　devices　and　tunable　thermal　emitters　based　on　controllable　crystallization　of　phase-change　materials.