With the expanding understanding of basic knowledge concerning respiratory function and technology of respirator, mechanical ventilation has become an important interventional armamentarium to improve gas exchange and decrease respiratory work. It is one of the important means to enhance oxygen delivery, protect the lung, and restore homeostasis in the treatment of multiple organ dysfunction syndrome. The progression in medical sciences and increasing data pertaining to evidence-based medicine have also render the use of mechanical ventilation standardized with more appropriate indication. Under the aforementioned conditions, it seems to be essential that the indications and the operation and manipulation of the sophisticated ventilator should be standardized in the care of critically ill patients. At the same time, accumulation of clinical experiences in recent years with abundant relevant data as a result of multi-center studies have furnished highly valuable information to accomplish this effort. Based on evidenced-base data, the Chinese Society of Critical Care Medicine (Chinese Medical Association) held a consensus conference to draft a guideline for the recommendation of mechanical ventilation to categorize all the information gathered from the literature into five grades from A to E, with A being the highest, according to a modified Delphi criteria, which were adopted by the International Sepsis Forum held in 2001. After further nationwide inquiries and conscientious discussions, this guideline has been drafted pending further addition and correction. This guideline chiefly covers the following aspects: the choice of mechanical ventilation for critically ill patients, the aim and indication of mechanical ventilation, non-invasive positive pressure ventilation, regulation of modes and settings of the ventilator, etc. With implementation of the guideline, it is hoped that the clinical use of mechanical ventilation in the critically ill patients will be more or less standardized. The guideline will be updated when new knowledge is available.