Phase-change　materials　were　highly　promising　for　next-generation　nonvolatile　data　storage　technology　and　their　properties　were　usually　improved　by　doping.　In　this　paper,　the　pronounced　effects　of　Sn　doping　(0%,　10%,　30%)　on　crystallization　behaviors　of　Ge2Sb2Te5　(GST)　film　induced　by　a　picosecond　pulsed　laser　were　investigated　in　detail.　The　TEM　observations　presented　the　crystallization　threshold,　melting　threshold　and　ablation　threshold　all　decreased　with　the　increasing　of　Sn　doping　while　the　crystal　structure　and　crystallization　behavior　has　not　been　changed.　After　single　pulse　Gaussian　laser　irradiation,　the　morphology　of　crystallized　films　for　GST　and　Sn-doped　GST　all　presented　an　ingot-like　microstructure　at　higher　laser　fluence　and　equiaxed　crystal　microstructure　at　lower　laser　fluence,　which　was　mainly　caused　by　the　temperature　gradient.　The　local　grain　refinement　was　found　in　GSTSn30%　films　because　weaker　Sn-Te　bond　(359.8　kJ/mol)　replaced　the　stronger　Ge-Te　bond　(456　kJ/mol),　which　was　also　proved　by　X-ray　photoelectron　spectroscopy　(XPS).　This　eventually　led　to　a　decline　in　nucleation　energy　barrier　and　increased　nucleation　rate.