The invention belongs to the field of research of biomedicines, and particularly relates to application of a human DNAJC24 gene as a target to preparation of medicines for treating lung cancers or medicines for diagnosing the lung cancers. Based on extensive and profound researching finding, by adopting a RNAi method, expression of the human DNAJC24 is regulated-down, so that proliferation of thelung cancer cells can be effectively inhibited and cell apoptosis is promoted, and a growth progress of the lung cancers can be effectively controlled. According to the siRNA or a nucleic acid construction body including an siRNA sequence and chronic viruses provided by the invention, the proliferation velocity of the lung cancer cells can be specifically inhibited, the cell apoptosis of the lungcancers is promoted, cell cloning of the lung cancers is inhibited, cell invasion of the lung cancers is inhibited, cell transferring of the lung cancers is inhibited, and growth of the lung cancers is inhibited, so that the lung cancers can be treated, and a new direction is developed for treatment of the lung cancers.