Security and stability standards of power grids are the basic norm of power system planning and operation."Security and stability guide of power systems" is China's reliability standard which has been in use since 1980s.The guide defines several levels of contingency according to the severity，and requires different defense plans.It has played an important role in security and stability during the period of rapid development of power grids.In 2011，the Central Government of China promulgated"Regulations on accident investigation and handling of electricity safety emergency"，which makes new requirements on grids and power companies from the perspective of load loss.Electricity utilities in China should review their security and reliability standards at present.The paper describes the security and stability standards carried out by the major Western developed countries，compares them with Chinese standards，and makes some useful suggestions for the next version of China's reliability standards.