In the process of implementing the regulations on site selection for underwater crossing buildings in clause 5.3.1 of Navigation Standard of Inland Waterway,we find the regulation that underwater tunnel must be laid away from anchorage is not always scientific and reasonable,due to vertical depth of the tunnel is not taken into account.Based on surveys,statistics,and analysis of anchor penetration depth and tunnel buried depth,we hold that installation and operation of the anchorage do not affect the safety of the tunnel structure,if the thickness of the cover at the top of the tunnel is greater than anchor penetration.Therefore,it is very necessary to amend the regulations that underwater tunnel must be laid away from anchorage in related navigation standards.