Abstract: With the development of pipeline transportation industry, the more and more requirements to the characteristics of steel pipe to be used are put forward. On the basis of analysis on the influence of the chemical compositions of steel materials and metallographic structures to the characteristics of steel pipe, as well as different requirements on the pipeline transportation environments and engineering environments, several calculation methods on toughness indexes of gas transmission pipelines are provided in the paper. It is pointed out that the characteristics of steel pipe are mainly controlled by the chemical compositions of steel and steelmilling process.