The purpose of this paper is to determine the safe operating window of subsea tree installation through analysing the sensitivity of multiple environmental parameters. In this paper, the wave height, period, phase angle and the sea surface current speed are taken as the evaluation factors of the marine environment, and a sensitivity ranking of these four factors is obtained by orthogonal analysis. The lateral offset and axial velocity of the tree, the axial deformation and von-Mises equivalents stress of the pipe are taken as constrain factors in sensitivity analysis. Results show that the wave height and period are the most significant affecting factor in sensitivity analysis. Finally, based on the given installation evaluation criteria, the installation operation window of the tree under different sea conditions are studied.