Abstract: A bulk absorption laser energy calorimeter operating in non-standard environment was designed. The thermal radiation, conduction and air convection of the calorimeter were analyzed, and its heat exchange equations were derived. The mathematical model of thermal loss of the calorimeter was established. The thermal loss in the process of temperature rising was compensated based on the model. The measurement repeatability error of the calorimeter for different input laser pulses was decreased from 4.7% to 0.6%, and the negative influence of thermal loss was removed. When the copper-constantan thermal couple was used to measure the same temperature difference in different environments, the calorimeters output changed greatly, it increased by 30% when the environment temperature increased from -40℃ to 70℃. Laser energy measurements were carried out at different temperatures in an environment controlled chamber, and the correction coefficients of the calorimeter at different temperatures were obtained. The dependence of the coefficients on environmental temperatures was determined by using the least square method. The impact of the environment temperature variation on measurement result was corrected.