This paper probes into the temporary navigation in the open channel for the construction of the Longxikou navigation power junction. Utilizing a mathematical model and a real ship test，it studies the flow conditions for temporary navigation and trial navigation results after the local dredging of the open channel. The mathematical model simulates the water depth and flow velocity of the temporary channel formed by the local dredging of the open channel for construction，both of which meet the requirements of ships for safe navigation. Under the loading and no-load conditions of vessels with different tonnages，the real ships in the test can safely go up and down through the temporary channel of the open channel for the construction of the Longxikou navigation power junction，which provides a basis for determining the navigation scope and scale of the temporary channel during the construction of the junction.