Objective To establish a rat model for lung injury induced by chest impact trauma. Methods Eight-four healthy male Sprague-Dawley rats were randomly divided into 7 groups (n=12) and were subjected to different chest impact energies (2.7,2.0,1.8,1.5,1.2,0.9 and 0 J) to induce bilateral lung injury using a self-designed device. The circulatory and respiratory functions were monitored before and after injury. The rats were sacrificed 120 min after chest impact. The morphological changes of the hearts and lungs were observed and graded pathologically. The wet/dry mass ratios of lungs and the protein contents in bronchoalveolar lavage fluid were determined. Results It was found that rats in the 1.2 J group developed bilateral lung contusion without substantial cardiac muscle trauma, and the animals had a low mortality. Conclusion Our self-designed device can satisfactorily produce lung injury model induced by chest impact trauma, and 1.2 J might be an ideal option for following studies.