Temperature distribution in a parallel-plate heater with the cooling of pulsating flow is theoretically studied. The results indicate the temperature of the heated plate fluctuates periodically as the flow pulsates. Effects of the wall thickness and its thermal properties, pulsating period and amplitude are analyzed based on the theoretical result. The fluctuation amplitude and the phase-lag of the outer surface temperature are magnified by the increase of plate thickness and the decrease of thermal diffusivity and pulsating period, and vice versa. It should be noted that the temperature difference between the outer wall and the inner wall, and the heat difference between the heat source and transported by the fluid caused by the unsteady condition should not be ignored. The results of the present study can be used to obtain a precise temperature fluctuation and the variation of the heat flux in unsteady flow condition. (C) 2014 Elsevier Ltd. All rights reserved.