Kovar　alloy　and　DM308　glass　were　bonded　with　YLS-6000　fiber　laser.　The　effect　of　interlayer　on　the　strength,　interface　structure　and　interface　bonding　mechanism　was　investigated.　The　diffusion　behavior　of　interface　elements　is　analyzed.　The　results　showed　that　the　Mo-Mn-Ni　interlayer　can　reduce　the　cracks　at　the　edge　of　the　joint,and　Ni2O3-MnO2-B2O3　interlayer　can　reduce　the　number　of　micro　cracks　and　the　number　of　bubbles　on　the　glass　side.　The　weakest　part　of　the　4J29　/　DM308　laser　welding　joint　is　near　the　glass　side,　which　breaks　through　the　bubble.　The　biggest　shear　strength　of　Mo-Mn-Ni　interlayer　joints　is　10.96　MPa.　The　biggest　shear　strength　of　Ni2O3-MnO2-B2O3interlayer　joints　is　13.46　MPa.　The　thickness　of　Ni2O3-MnO2-B2O3　interlayer　transition　layer　is　about　30-40　μm.　There　is　obvious　dendrite　growth　in　the　transition　layer.　The　results　of　joint　interface　XRD　phase　analysis　show　that　the　interface　transition　layer　is　FeSiO3　and　Fe7SiO10.　It　is　belong　to　Fe　and　Si　cubic　complex　oxides.　The　results　of　EDS　analysis　showed　that　Fe,　Co,　Ni,　Al,　Na　and　Si　elements　had　diffused　in　the　whole　interface　region.　The　interfacial　bonding　mainly　depends　on　chemical　reaction　and　element　diffusion.　©　2018,　Editorial　Board　of　Transactions　of　the　China　Welding　Institution,　Magazine　Agency　Welding.　All　right　reserved.