OHSAS18001 standard by: constitute a range of 2 Normative references 3 Terms and definitions, four elements of occupational health and safety management system and other four series. Standard specifies 17 terminology definitions, including "hazard", "risk", "accident" is featured four terms have 18001. Chapter 4 is the standard main content, specifies the requirements for occupational health and safety management systems. Identical structure and ISO14001 standards, increased from a five elements, two elements of the next 17 points, reflecting the PDCA cycle and management.