Abstract: The thermal energy loss of the bulk absorption laser energy meter caused by the thermal radiation, heat convection and conduction was analyzed based on the basic heat-transfer theory. The mathematical model of thermal loss for the energy meter is established according to the analytical result. The curves of the measured data were fitted with the math model and least square method. The fitted curve is quite similar to the actual curve of the temperature drop. The measurement repeatability of the energy meter is improved greatly after the measured data is compensated and corrected by the fitted curve. The work is useful for the development of bulk absorption laser energy meters.