The location of the closure gap belongs to the area where the velocity increases suddenly and the flow field is complex,so it is of great significance to accurately predict the scour pattern for the structural design and safe operation of closure gap.Relying on a large-scale overseas reclamation port project,with the aid of CFD software,we carried out the 3D numerical calculation of local scour characteristics of closure gap of different structures under strong overtopping waves during the construction period,and obtained the distribution regularities of flow field and local scour pattern around closure gap respectively,thus provided some suggestions on erosion protection.The results show that the flow field around closure gap is complex,but there is a certain law,and its characteristics have a certain corresponding relationship with the local scour factors of the closure gap.If a sand retaining structure is set in the closure gap area,there is a risk of scouring below it,which is easy to form a scouring channel.When scour develops to a certain extent,it will disturb the original flow field behind the closure gap and aggravate the scour degree at the bottom and back of the closure gap.