Objective: To study the therapeutic effect of Compound Biejia Ruangan prescription (CBRP) on rat model with pulmonary fibrosis induced by bleomycin. Methods: Fifty-four male Sprague-Dawley rats were randomly divided into 6 groups (9 rats in each group). From the first day to the 28th day of the experiment, except to those in the sham-model control group that were treated with normal saline, the same amount of bleomycin injection as the normal saline given to the control group was given through endotracheal instillation to all the rats in all the other groups. From the 29th day of the modeling, CBRP solution of different dosages was respectively injected into the rats in the high, moderate and low CBRP dose group, while equal volume of normal saline was given to those in the sham-model control group and the model control group, and an equal volume of prednisone solution was given to rats in the prednisone group. On the 80th day, the high-resolution computerized tomographic (HRCT) images were observed on an equal footing, and HRCT-pathology was correlatively studied. Results: Different HRCT pathological changes were shown in the rats with pulmonary fibrosis, such as lung consolidation, thickening of interlobular septum and interlobular mesenchyma as well as lobular deformation, nodule shadow, abnormal brochiovascular tract, thickened pleura with irregular junction and polished glass-like dense shadows. Honeycomb lung was observed in some cases. Pathological sections showed fibrotic proliferation of lung tissues and noticeable pulmonary interstitial fibrosis. CBRP could improve HRCT images of rats with pulmonary fibrosis, and lower fibrotic proliferation of the lung tissue.Conclusion: CBRP plays its therapeutic role possibly through its effect on the structure of the lung in rats with pulmonary fibrosis.