In the environment of deep water,large flow velocity and low visibility,the construction efficiency of underwater rubble-bedding leveling is low,and it is difficult to ensure the construction accuracy.To solve these problems,we carry out a research on the automatic underwater rubble bed leveling system.To achieve the key technology of the research,we design dedicated test units for the tests,which were divided into several groups based on various laying states of stone,various leveling speeds and various thicknesses of stone.The value of the scraper leveling propulsion resistance is 23.08 kN?m according to the tests,and the result provides crucial parameters for the research.