Abstract: A thermal model for evaporator and condenser section of heat pipe with axially swallow-tailed microgrooves was developed based on heat and mass transfer of thin liquid film. The capillary radius under different heat load conditions was obtained from the Laplace-Young equation. The effect of heat load on the temperature drop of evaporator and condenser section was discussed and the total temperature drop of heat pipe was obtained. An experimental research on the heat pipe was presented and the effect of heat load on the temperature drop was analyzed in different temperature of cold sources. The results showed that the thickness of liquid film in the microgroove increased along the axial direction; the temperature drop of evaporator and condenser section increased with a rise of heat load. The analytical results were compared with experimental results and found to be in good agreement, and the accuracy of the model was further verified by the experiment.