There is still disadvantage in animal model for lung cancer study, no matter what is xenograft nude mice or rats/mice lung neoplasm induced by carcinogenesis.The purpose of the current investigation is to explore a simple and convenient and reliable method for lung neoplasm animal model. The prepared 36 female Sprague Dawley (SD) rats, with the range from 180 to 220g of body weight, were randomly divided into two groups, each group included 18 rats. In the study group, the rats were given 2mg of 3, 4-benzopyrene soluting in 0.2mL corn oil every two-weekly pulmonary injection for 4 times through right middle-chest percutaneous puncture under control of anaesthesia by pentobarbital sodium i.p. The controls were only given 0.2mL corn oil injection simultaneously. The rats were sacrificed after suffering from dyspnea, and the survived rats were sacrificed at narcotism in 1 year after the first 3, 4-benzopyrene toxicosis. Lung, brain, liver, esophagus and stomach of all rates were anatomized in search of tumor. No