On the basis of the river physical model test of some low-head navigation and hydropower project ,the test of a remote-control self-propelled model ship was carried out, the influence of cross-flow caused by the construction cofferdam on the ship model has been analyzed. The results show that the degree of influence of cross-flow on ship model sailing mainly is related to the region and size of the cross-flow as well as the ship model sailing velocity to the bank. Research methods can provide a reference for hydraulics research and waterway engineering design.