According to field data of the Lower Yellow River,the river shrink variation has been analyzed.The cross section area of river channel and water level at Q=3000m 3 /s have been chosen for index of river channel shrink.Water sediment coefficient (averaged sediment concentration to averaged discharge)has been used as the variation of water and sediment condition.The relationship between river channel shrink and water sediment coefficient has been established.The results indicate that the river shrink has a definite relation with water sediment coefficient in the Lower Yellow River.