Spatters　in　laser　penetration　welding　of　aluminum　alloys　can　pollute　the　focusing　system,　which　would　affect　the　processing　stability　and　welding　quality.　Furthermore,　the　spatter　characteristics　can　reflect　the　laser　welding　process　in　some　degree.　In　this　paper,　the　spatter　characteristics　in　fiber　and　CO2　laser　welding　of　6061-T6　aluminum　alloy　are　investigated,　and　the　reasons　for　the　difference　of　the　spatter　characteristics　are　discussed.　Dynamic　behavior　of　spatters　is　recorded　in　real-time　using　a　high-speed　camera.　The　spatter　particles　are　captured　and　measured　experimentally.　Probability　density　functions　(PDFs)　about　the　spatter　velocity　and　particle　size　are　fitted　by　Ordinary　Least　Squares　(OLS)　method　in　γ2　test.　The　result　indicates　that　the　spatter　speed　obeys　Gaussian　distribution　and　the　particle　size　follows　Lognormal　distribution　in　both　cases.　The　statistical　speed　of　spatters　is　slower　and　the　statistical　diameter　is　greater　in　CO2　laser　welding.　Moreover,　under　95%　confidence,　the　particle　size＇s　PDF　is　more　subject　to　Lognormal　distribution　with　a　much　smaller　residual　mean　square　(RMS)　of　3.26×10-3　in　fiber　laser　welding　than　that　of　0.109　in　CO2　laser　welding.