Abstract: This paper introduces the structural style of a marine laminated insulation flexible pipe, and derives the computational method of theoretical heat transfer coefficient. To test the insulating property of the flexible pipe, two experimental programs for insulating property in steady state and transient state were designed as per relevant specifications, and are used respectively to test the laminated insulation flexible pipe. The data measured in the experiments were recorded in detail and processed and analyzed accurately. It is discovered through correlation of theoretical value and experimental value that the heat transfer coefficient obtained from experiment in transient state is lower than that from experiment in steady state, and the heat transfer coefficient measured from the later experiment is closer to the theoretical value. The comparison of these two experimental programs shows that the data obtained from the steady-state experiment program is more accurate and reliable. Furthermore, the causes for the lower experimental data obtained than the theoretical calculated value were analyzed, suggesting that the negligence of insulation effect of air occluded in the flexible pipe architecture at the time of theoretical calculation is the leading cause.