A finite-element model to predict the temperature field and thermal stress distribustion on membrane type water-wall in boiler of supercritical 600 MW unit has been established.The results of calculation show that the maximum temperature had appeared in the centre of tubes and fins toward the fire side

and the maximum temperature difference between inner and outer surface of the water-wall tube was 29 ℃.The maximum thermal stress

i.e.1.77 GPa

was found in the interface between water-wall tubes and fines

and the deformation in the center of side toward fire was large

the maximum deformation of inner and outer wall surface was 0.193 mm and 0.222 mm respectively.