 To widely implement painless gastroscopy is required by diagnose and treatment with gastroscopy due to the large number and significant suffering of the patients. Also, development and exploration of anesthesiology will be bound to prompt the development and exploration of painless gastroscopy. However, the anesthesia risk of painless gastroscopy are usually higher than that of general anesthesia performed in operating room due to the condition, monitoring and equipments as well as the staffing for its implementation. Thus, the finding of a safe and convenient approach for general anesthesia will have a profound impact on a full promotion and implementation of comfortable care. 