The　method　for　manufacturing　grid　panels　that　deposits　material　directly　on　the　substrate　layer　by　layer　can　considerably　improve　the　production　efficiency　and　reduce　cost.　In　the　process　of　forming　grid　panels,　the　formation　of　the　base　layer　and　the　entire　thermal　process　determine　whether　the　upper　layer　can　be　successfully　formed.　The　parameters　of　the　finite　element　heat　source　model　were　generated　by　measuring　the　morphology　of　the　base　layer　for　wire　arc　additive　manufacturing　through　different　plate　thickness　experiments.　The　influence　of　substrate　thickness,　preheating　temperature,　and　distance　from　the　edge　on　the　width　of　the　base　layer　for　wire　arc　additive　manufacturing　was　investigated　by　finite　element　simulation.　The　experimental　results　show　that　with　the　increase　in　the　thickness　of　the　substrate,　the　forming　width　of　the　base　layer　decreases　significantly.　With　the　increase　in　the　preheating　temperature,　the　width　does　not　increase　significantly　when　the　temperature　is　within　80,　whereas　the　width　increases　significantly　when　the　temperature　exceeds　120.　The　decrease　in　the　distance　from　the　edge　has　only　a　slight　effect　on　the　forming　width　beyond　the　range　of　20mm　and　gradually　increases　the　forming　width　within　the　range　of　20mm.　When　the　distance　from　the　edge　is　10mm,　the　temperature　of　the　entire　edge　base　plate　reaches　500,　and　the　collapse　tendency　of　the　base　plate　becomes　obvious.　On　the　basis　of　the　results　of　the　experiments,　the　mathematical　model　of　the　formation　of　the　base　layer　is　established　according　to　the　thermodynamic　theory　to　help　determine　the　heat　source　parameters　and　combined　with　the　statistical　least　square　method.　This　novel　prediction　method　can　be　extended　to　the　analysis　and　study　of　the　heating　process　of　wire　arc　additive　manufacturing　with　different　process　parameters　and　plate　thicknesses.　©　2020,　Editorial　Board　of　Journal　of　Tianjin　University(Science　and　Technology).　All　right　reserved.