One of the most important design challenges for engineers is the design for the installation of the pipeline including the pipe-in-pipe (PIP) system. A design underestimation could result in serious damage, while overestimation would result in high operation costs. An optimised modelling method is definitely required for the PIP system. The modelling of a finite element single pipe-lay simulation has been studied and discussed by many authors, and is very much understood by the people in the industry. However, modelling complex PIP systems for pipe laying simulations is quite challenging. To build the most economic finite element (FE) model for pipe-lay simulation of PIP systems, various modelling aspects of the installation were studied separately. In this work, three types of FE models which are two models with different simplifications and one actual PIP model were established and compared. Finally, a method for the optimization of performing PIP installation is presented. © 2016 Taylor & Francis Group, London.