A　CALPHAD-coupled　finite　element　model　of　dissimilar　AZ31/ZK61　resistance　spot　welding　was　established　in　this　work.　The　coupled　effect　of　phase　transformation　and　heat　transfer　was　considered　in　this　model,　which　presents　the　solid　fraction　contour　evolution　within　the　joint.　During　the　cooling　stage　of　AZ31/ZK61　resistance　spot　welding,　a　low-solid-fraction　layer　appears　within　the　partially　melted　zone　of　the　joint.　The　continuous　liquation　crack　in　the　AZ31/ZK61　resistance　spot　weld　exhibits　a　pattern　similar　to　the　low-solid-fraction　layer　plotted　by　the　CALPHAD-coupled　finite　element　model.　In　the　case　of　AZ31/ZK61　resistance　spot　welding　with　a　Zn　interlayer,　no　low-solid-fraction　layer　appears.　Due　to　the　consideration　of　the　coupled　effects　of　phase　transformation　and　heat　transfer,　the　CALPHAD-coupled　finite　element　model　possesses　the　capability　to　analyze　the　liquation　cracking　susceptibility　of　ZK　series　magnesium　alloy,　which　exhibits　significant　eutectic　reactions　during　non-equilibrium　solidification.　©　2023,　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　London　Ltd.,　part　of　Springer　Nature.