Based on the principle of minimum potential energy, the nonlinear mechanical response of steel lazy-wave riser during installation and transfer is studied by taking the whole riser as a single continuous pipe section. This method does not need to study the whole riser separately, can simply and effectively deal with the riser-seabed interaction, avoids the complexity of contact detection, is very flexible to adapt to new loads, constraints or boundary conditions, and can improve the numerical calculation efficiency in the design and application of deepwater riser. It is found that: the height of the upper arch point and sag point first decreases and then increases, while the arch bending height first increases and then decreases in the process of the transfer of the riser to the reduction of the horizontal span; the tension at the suspension point decreases and then increases, while the inclination at the suspension point changes very little. The numerical analysis results are of certain reference value for the design of steel lazy-wave riser in deep water.