2, the scope is different: nursing secondary quality is mainly for a single patient or patient group quality of care, focusing on the patient's safety and comfort, such as the patient's quality of sleep, hygiene and environment, diet and other aspects. Nursing three quality control needs to use the methods and techniques of systems engineering, covering a wide range, need to comprehensively consider the patient, health care personnel, medical equipment and medical environment and other aspects, in order to improve the quality of nursing care and medical service level of the hospital.