Abstract: The present application relates to an installation method for a closure joint of an immersed tunnel, and belongs to the technical field of closure joints; the installation method comprises the steps: establishing a first coordinate system; distributing feature points; installing the N+2 tube coupling; installing an N+1 tube coupling and pushing out a push-out segment; wherein, the first coordinate system is established at a tail end of an N+3 tube coupling, breakthrough points N+1S and N+1W are distributed at a head end and a tail end of a N+1 tube coupling respectively, breakthrough points DS and DW are distributed at a push-out segment, and breakthrough points N+2S and N+2W are distributed at a head end and a tail end of a N+2 tube coupling respectively; and coordinates of the breakthrough points DS, DW, N+1S, N+1W, N+2S, N+2W in the first coordinate system are calculated respectively; the installation method can improve the installation accuracy of the closure joint and is easy to operate.