Abstract: Objective: To evaluate the factors causing and the treatment of postoperative phrenitis and mania following thoracic surgery. Methods: Three patients with postoperative phrenitis and mania following thoracic surgery were discussed. Results: Thanks to earnest observation, timely diagnosis and treatment, the three patients all recovered. Conclusion: The factors involved in postoperative phrenitis and mania following thoracic surgery include three aspects: anesthetic factors, psychological factors, and surgical factors that may include surgical trauma, oxygen deficiency, lung infection, malnutrition and so on. Once postoperative phrenitis and mania occurs, treatment with antipsychotics is the best treatment.