Abstract: Objective 　To stuoly and construct model of experimental rats malignant pleural mesothelioma (MPM), Which will provide us with morphologieal forndation for clinical diagnosis and curing MPM. Methods 　120 wister rat s were divided into two groups randomly group one was injected asbestos fibrous mixed fluid of YunNan Dayao ( test group ) and group two was injected sterilized 0. 9 % NaCl ( control group) . Died and dying rats were performed by autopsy Observing the pathological change in tumor and interrelated organ. 15 cases of tumor were performed by immunohist rochemical staining EMA and Vim. Results 　66 rat s suffer from MPM among 92 rats of experimental rats, The induction rats was 71. 74 %.The nodular type MPM of pathological change were dominated (72. 73 %) in the micrography. The Pathological change included of epithelial type, fibrous type and mixed type in the micrography. 13 cases of tumor was performed by immunohist rochemical staining EMA and Vim were positive. 12 cases were hyperplasic lesions of mesothelial cell. Induced rat s' MPM had a higher similarity with human' s MPM, especially in pathogenicity, positions, histological type and biological behavior of invasion and metastesis. Conclusion 　Induced rat s'MPM in YunNan DaYao may be a valuable tumor model to study MPM measures of prevention, and to guide clinical diagnosis and treatment .