The temperature of exhaust pipe in offshore platform is very high. This high temperature will cause thermal stress in piping system and large force to connecting machine and hull structure during piping thermal expansion and contraction. Selection of expansion joint, pipeline arrangement, as well as type and structure of the supports have direct effects on the safety of connecting machine and hull structure. Static analysis and modal analysis are carried out with CAESARⅡ piping stress analysis software. The flexible factors of bend and tee of large diameter pipe are included as references. According to the calculation results, the primary stress and secondary stress of high temperature piping system can meet the standards.