Nanosecond　pulsed　laser　has　a　larger　melting　area　relative　to　ultrashort　pulsed　laser,　so　the　use　of　nanosecond　laser　greatly　alleviates　the　gap　limitation　on　brittle　transparent　materials/metal　materials　during　the　joining　process　using　ultrashort　pulsed　laser.In　order　to　determine　the　maximum　allowable　gap　for　nanosecond　laser　joining　of　brittle　transparent　materials/metals　and　the　influence　of　different　gap　conditions　on　the　joining　effect,　this　study　examines　the　effects　of　various　interface　gap　conditions　on　the　macro-　and　microstructure　as　well　as　the　mechanical　properties　of　quartz　glass/copper　joints.　It　is　found　that　the　joint　shear　strength　decreases　from　27　MPa　to　10.5　MPa　with　the　increase　of　the　interfacial　gap,　and　the　maximum　permissible　interfacial　gap　is　about　5　μm.　The　reason　for　the　large　error　bars　in　the　shear　strength　data　of　quartz　glass/copper　joints　is　mainly　due　to　the　common　intrinsic　cracks　in　brittle　and　hard　transparent　materials,　which　include　porosity　and　inclusion,　and　the　existence　of　porosity　and　inclusion　often　leads　to　the　shear　strength　of　a　discrete　and　accidental　nature.　In　addition,　it　is　found　that　the　causes　of　cracks　during　nanosecond　laser　joining　of　quartz　glass/copper　are　divided　into　two　categories　one　is　delayed　fracture　in　cold　cracking　and　the　other　is　thermal　cracking,　which　can　be　avoided　by　regulating　the　process　parameters.　©　2024　Chinese　Mechanical　Engineering　Society.　All　rights　reserved.