Effect　of　exit　width　on　evacuation　time　of　shopping　mall　is　a　key　issue　for　public　safety.　Based　on　the　site　observing　a　typical　shopping　mall　in　China,　the　proportion　and　walking　speeds　of　different　customer　groups　and　evacuation　capacity　of　exit　are　obtained　as　the　input　parameters　for　numerical　simulation　on　evacuation.　The　evacuation　model　of　STEPS　(Simulation　of　Transient　Evacuation　and　Pedestrian　movements)　is　used　to　simulate　the　evacuation　process　under　the　same　condition　as　on-site　observation.　It　has　been　found　that　there　is　a　good　agreement　between　the　results　of　observation　and　simulation.　The　results　indicate　that　there　is　a　critical　width　to　distinguish　whether　the　exit　width　affects　evacuation　time　or　not.　When　exit　width　is　less　than　the　critical　value,　the　evacuation　time　decreases　with　the　increase　of　the　exit　width.　If　exit　width　is　larger　than　the　critical　value,　the　evacuation　time　would　not　be　affected　by　exit　width.　Walking　speeds　of　the　customers,　the　internal　layout　of　the　building　and　the　number　of　evacuees　would　influence　the　critical　value,　while　they　do　not　affect　the　evacuation　capacity　of　exit.　©　2024　12th　International　Symposium　on　Project　Management,　ISPM　2024.　All　rights　reserved.