Numerical　simulation　technology　can　quickly　and　comprehensively　analyze　the　welding　process　and　is　widely　used　in　welding　related　research.　In　the　welding　process,　the　welding　heat　input　determines　the　distribution　of　welding　temperature　and　stress,　so　its　accurate　expression　plays　the　most　important　role　in　the　accuracy　of　simulation.　At　present,　the　description　of　welding　heat　input　is　completed　by　the　heat　source　model　substituted　in　the　simulation.　The　combined　heat　source　model　that　includes　multiple　single　heat　sources　is　particularly　concerned　because　of　its　flexible　use.　The　flexibility　of　the　combined　heat　source　model　comes　from　the　fact　that　it　can　be　a　combination　of　any　single　heat　source　model,　but　this　also　brings　difficulties　in　composition　selection.　In　theory,　the　composition　of　the　combined　heat　source　model　is　infinite,　and　the　advantages　of　the　combined　heat　source　model　can　be　reflected　only　when　the　combination　heat　source　model　can　be　accurately　determined　according　to　the　wel-ding　situation.　In　addition,　the　parameters　of　the　combined　heat　source　model　are　added.　There　are　shape　parameters　that　also　exist　in　the　single　heat　source　model,　and　it　also　includes　the　energy　coefficient　of　how　the　total　welding　energy　is　distributed　in　the　combined　heat　source　model.　How　these　parameters　should　be　adjusted　and　determined　is　a　question　that　must　be　answered　when　using　the　combined　heat　source　model.　In　different　welding　situations,　researchers　have　used　surface　heat　source　+　body　heat　source,　body　heat　source　+　body　heat　source　and　other　various　combinations.　They　can　be　divided　into　two　categories　according　to　the　purpose　of　using　the　combined　heat　source　model:　(1)　the　combined　heat　source　model　is　used　to　simulate　the　shape　of　the　molten　pool　that　is　difficult　to　express　by　the　single　heat　source　model;　(2)　the　combined　heat　source　model　is　used　to　correspond　to　different　parts　of　the　actual　welding　heat　source.　In　these　works,　the　application　of　the　combined　heat　source　model　improves　the　accuracy　of　simulation.　In　the　study　of　heat　source　parameter　adjustment,　the　energy　distribution　coefficient　of　heat　source　can　be　determined　by　observing　the　shape　of　simulated　molten　pool,　experimental　measurement　and　simulation　experience.　In　order　to　improve　the　efficiency　of　heat　source　shape　parameter　adjustment,　on　the　basis　of　trial-and-error　method,　the　emergence　of　digital　image　reco-gnition　technology　and　automatic　calibration　program　has　strengthened　the　application　of　computer　technology.　In　addition,　it　is　also　possible　to　consider　reducing　the　number　of　shape　parameters　when　designing　the　heat　source　model.　This　paper　introduces　the　composition　of　the　combined　heat　source　model　from　the　shape　of　the　molten　pool　and　the　distribution　of　energy,　then　summarizes　the　calibration　method　of　the　heat　source　parameters,　and　finally,　summarizes　three　application　scenarios　of　the　combined　heat　source　model,　and　points　out　that　the　application　of　computer　technology　should　be　strengthened　in　the　model　design　and　parameter　adjustment　in　the　future.　©　2022,　Materials　Review　Magazine.　All　right　reserved.