Objective The extremely xerothermic environment of desert easily causes heatstroke and consequently multiple organ damage.Few reports are seen at home and abroad on heatstroke-induced lung injury associated with dry heat of desert.This stud-y explored the changes of the injured lungs in heatstroke rats in xerothermic desert. Methods Forty-eight male SD rats were ran-domly divided into six groups of equal number: mild, moderate and severe heatstroke groups and their corresponding controls.The rats of the three heatstroke groups were exposed to a temperature of 41 ℃and humidity of 10%, while those in the three corresponding control groups to a temperature of 25 ℃ and humidity of 35% for 70, 110 and 145 minutes, respectively.Then all the rats were sacrificed and the bronchoalveolar lavage fluid ( BALF) and lung tissues were collected for observation of pathological changes, obtainment of lung in-jury scores, calculation of the wet/dry weight ratio of the lungs, measurement of the total protein level in the BALF, and determination of the malondialdehyde ( MDA) content in the lung tissue. Results The mild, moderate and severe heatstroke groups showed re-markable increases compared with the three corresponding control groups in lung injury scores (3.25 ±0.50, 6.50 ±0.58 and 8 ± 0.82 vs 1.25 ±0.50, 1.00 ±0.00 and 1.25 ±0.50), the wet/dry weight ratio of the lungs (3.50 ±0.57, 4.85 ±0.19 and 4.10 ± 0.07 vs 1.78 ±0.66, 1.67 ±0.68 and 1.67 ±0.25), the total protein level in the BALF ([93.51 ±5.54], [141.24 ±6.07] and [160.76 ±6.74] μg/mL vs [42.6 ±8.67], [45.25 ±6.78] and [41.68 ±3.62] μg/mL), and the content of MDA in the lung tis-sue ([1.79 ±0.08], [2.79 ±0.11] and [3.52 ±0.36] nmol/mg prot vs [1.21 ±0.12], [1.20 ±0.12] and [1.28 ±0.19] nmol/mg prot) .The lung injury scores, the total protein level in the BALF, and the content of MDA in the lung tissue were increased with the prolonging of the time of exposure to dry heat, while the wet/dry weight ratio of the lungs was the highest in the moderate heat-stroke group.The lung injury scores were positively correlated with the wet/dry weight ratio of the lungs, the total protein level in the BALF, and the content of MDA in the lung tissue (P<0.01). Conclusion Heatstroke in the xerothermic environment of desert can cause lung injury in rats, which deteriorates with the prolonging of the time of exposure to dry heat.As for the management of such heatstroke, more attention should be paid to the protection against lung injury.