The construction of the seawater projects across channel will occupy the navigation channel,thus the temporary channel shall be set up to reduce the influence on vessel navigation by project construction.Up to present,there is not a design regulation for the temporary channel.The design vessel,width,center line,depth and aids to navigation of the temporary channel are discusses.The temporary Longguxi channel of island and tunnel,Hong Kong-Zhuhai-Macau Bridge transforms 4 times during the whole construction.The design key technical data of the temporary channel and plan of aids to navigation are determined by special demonstration and expert discussion,and the feasibility of which has been proved feasible in the practical operation.It is shown that we should not design the temporary channel based completely on the requirement to the normal channel,but should integrate it with the construction plan,vessel dispatch and site supervision.