Abstract: Consolidated and undrained triaxial tests are carried out to study the steady-state strength of silty soil in the Yellow River Delta. First three groups of silty soil samples with different dry densities, i.e., 1.55, 1.65 and 1.75 g/cm3, are prepared, the influence of the initial dry density on the steady state line is studied, and uniqueness of the steady state line is discussed. Then five groups of silty soil samples with different clay contents , i.e., 10%, 14%, 17%, 24% and 30%, are prepared, and the influence of the clay content on the steady state strength line is quantitatively analyzed. A conclusion is drawn that the silty soil with the clay content of 10% has the maximal steady state strength. Reasons of such phenomena are analyzed, and eventually the correlation function between the steady state strength and the clay content is established.