Abstract: Objective: To explore reasonable position for thoracic operation through observing the application effect of three kinds of lateral decubitus placement methods in the thoracic operation, Method: The patients undergoing elective thoracotomy with general anesthesia were divided into three groups randomly with 80 cases in each group. A1 group: double arm stretching forward with double hand normal to body on the shelf; A2 group: using "holding ball" method; A3 group: using "sleeping"method. We compared the complications, posture time and operator satisfaction among three groups. Results: No statistical difference of complications was found among three groups. The posture time and operator satisfaction in A3 group were better than those in the other two groups. Conclusion: Sleeping type lateral position in thoracic surgery could reduce posture time and improve the operator's working efficiency.