In　this　paper,　fiber　laser-arc　hybrid　welding　plasma　was　studied　by　using　the　multiple-imaging　method.　Four　images　of　plasma　with　different　light　intensity　areas　can　be　simultaneously　observed　in　a　picture.　The　arc　plasma　and　metal　plasma　can　be　distinguished　in　the　high　light　intensity　area,　and　the　arc　plasma　has　an　approximate　average　light　intensity　distribution.　The　metal　plasma　is　mainly　concentrated　above　the　keyhole,　and　its　temperature/electron　density　first　increases　and　then　decreases　along　the　laser　beam　direction.　The　light　intensity　of　plasma　is　approximately　proportional　to　its　temperature　in　the　low　light　intensity　area,　and　its　morphology　is　similar　to　its　temperature　field　profile　obtained　by　numerical　simulation.　By　using　the　multiple-imaging　method,　the　high　light　intensity　area　morphology　of　plasma　can　be　measured,　and　the　simulation　results　of　the　plasma　temperature　field　in　the　low　light　intensity　area　can　be　verified.