This paper shows the temperature distribution of double hull compartment and of cofferdam in a large LNG Carrier. In LNG Carrier, due to the lower cargo temperature($-163^{circ}C$), structures are forced to lose their strength if additional heat is not supplied. So it is very important to estimate the temperature distribution and the heat flux needed to maintain the structure properly. The temperature of each compartment is obtained using 2-dimensional model analysis and compared with 3-dimensional results. And also this paper gives preliminary estimation of pipe length to supply necessary heat flux in bare pipe and finned pipe.