Abstract: A digital algorithmanalytical recursion scheme method for the structural dynamics to solve the earthquake response problem of the soft clay foundation is put forwarded. From the outcomes of the research, the analytical recursion scheme method can obtain more accurate calculating results. It is a general numerical algorithm in nonlinear vibration problem, especially suits for the seismic response analysis of soft clay foundation. For onedimension earthquake response analysis of soft clay foundation, a more sufficient comparison is taken between the analytical recursion scheme method and the equivalent linear method for the result of account in manifold ground. The outcomes show: （1） In the soft soil seismic response analysis, the difference between these two methods is relatively greater;（2） When the value of the inputting earthquake waves are greater, the difference between these two methods is relatively greater; （3）For the medium hardness soil layer earthquake waves was stronger, the two methods got similar results. The validity of the proposed analysis method and computer program has been verified.

Key words: soft clay foundation, onedimension soil layer, nonlinear earthquake response, digital algorithm, analytical recursion scheme