Abstract: By considering the geometrical nonlinearity, a new method for the nonlinear random vibration of a free spanning submarine pipeline is presented. Firstly, using modal analysis, the implicit system is represented as an explicit nonlinear system whose nonlinear terms are based on the combination of modal coordinates. Secondly, using the pseudo-excitation method, the stochastic equivalent linear system is established. Based on the equivalent linear system, the nonlinear response of the pipeline can be gained conveniently. The proposed method is used in the analysis of a suspended pipeline. The results show that the method can consider geometric nonlinearity and has high efficiency. The influences of the spans, water-depths, diameters and residual stresses are analyzed. The results show that the geometrical nonlinearity has a significant influence when the span was long. And the responses are remarkable when the span is long, the water-depth is shallow, the diameter is small and the initial compression stress is high. It implies that the considerable attention should be paid when these conditions exist in free spanning submarine pipelines.