The　mechanism　of　the　interface　layer　formation　between　steel　and　aluminum　dissimilar　materials　is　unclear　by　now.　An　interfacial　bonding　was　investigated　by　joining　steel　sheets　to　6061　aluminum　sheets　under　a　thermal　and　mechanical　coupled　loading.　The　effects　of　temperature　and　zinc　coating　on　microstructural　evolution　and　shear　strength　of　the　interface　layer　were　both　studied.　The　experimental　results　showed　that　the　interface　layer　between　the　uncoated　steel　and　aluminum　was　mainly　composed　of　FeAl3　intermetallic　compound　(IMC).　The　shear　strength　of　the　joint　increased　with　temperature.　The　existence　of　the　zinc　coating　was　able　to　lower　the　temperature　to　form　the　interface　layer　and　improve　its　shear　strength.　The　interface　layer　between　the　zinc　coated　steel　and　aluminum　was　mainly　composed　of　Fe2Al5Znx　and　Al-Zn　eutectic　phases　with　a　lower　micro　hardness.　That　suggested　that　the　brittleness　of　the　interface　layer　composed　of　the　Fe-Al　IMC　could　be　avoided　by　modify　the　zinc　coating　and　temperature.　A　zinc　foil　was　added　between　steel　and　aluminum　sheets　to　amplify　the　interface　layer　for　microstructure　observation.　Based　on　the　results　an　interface　bonding　model　of　steel　and　aluminum　dissimilar　materials　considering　the　temperature　and　zinc　coating　was　proposed.