Abstract: This paper compared the stability factors of beams in various international codes for design of steel structures，and corresponding load factors． The results of reliability analyses specified by AISC code and EC3 are also introduced． The main conclusions are as below: 1) Stability factors from large to small in codes are Canada，AISC and China and Japan; 2) except the Chinese code，the stability factors tend to be average of test results if their live load factors are also greater; 3) the reliability index analysis of steel beam specified by AISC reveals that its safety index is less than required，especially when the live load is predominant; 4) GB 500172003 has relatively large stability factors but the smallest live load factors，implying the least safety index．