In situ measurement of temperature distribution in a Proton Exchange Membrane Fuel Cell (PEMFC) stack is conducted by embed 36 T-type thermocouples on the MEA surface in four representative cells. Temperature increasing rate can get to 2.5 degrees C min(-1) at 1000 mA cm(-2). The largest temperature difference is observed in the middle of the stack, and the temperature difference can reach 17 degrees C at the bottom of the stack. The non-uniformity of temperature distribution is found to be improved by increasing the operation pressure, and the largest temperature difference decreases by 2.5 degrees C when the absolute operation pressure is increasing from 100 kPa to 150 kPa. (C) 2014 Elsevier Ltd. All rights reserved.