During　the　COVID-19　pandemic,　Chinese　universities　implemented　many　interventions　against　SAR-CoV-2　transmission.　Close　contact　is　thought　to　be　a　major　transmission　route.　However,　the　effect　of　university　closure-related　interventions　on　infection　risk　amongst　students　is　still　poorly　understood.　In　July　2022,　we　conducted　an　online　survey　of　2,400　university　students　in　Beijing　and　Shanghai.　Combined　with　real　human　behaviours,　we　evaluated　the　infection　risk　via　close　contact　during　both　periods　of　university　closures　and　non-closures.　During　the　non-closure　period,　undergraduate　and　postgraduate　students　spent　the　longest　close　contact　time　in　classrooms　and　graduate　student　offices,　averaging　1.9　h　and　2.2　h,　respectively.　During　university　closures,　students　spent　the　longest　close　contact　time　in　residences　(dormitories　and　homes),　reaching　up　to　2.8　h.　Catering　places　and　residences　were　the　two　main　indoor　environments　for　viral　exposure　via　close　contact.　Viral　exposure　did　not　differ　significantly　by　education　background　or　gender　(p　＞　0.05)　but　did　by　intervention　levels　in　university　or　community　(p　＜　0.05).　The　infection　risk　decreased　by　30.0%　for　resident　students　and　63.6%　for　non-resident　students　during　university　closures.　The　findings　could　provide　scientific　support　for　intervention　policy-making　during　public　health　emergencies　such　as　COVID-19　pandemic.