Abstract: Elaborated in the essay are the key changes of the 2008 edition of China National Standard GB/T 3091——Welded Steel Tubes for Low Pressure Liquid Conveyance, and a comparison between the 2008 edition and the 2001 edition thereof. In the 2008 edition, the data of OD, W.T. and W. per length unit are directly borrowed from the national basic standard of GB/T 21835-2008——Dimensions and Weights per Length Unit of Welded Steel Tubes, while information concerning the spiral SAW pipe and necessary inspection and test items are added. The revised latest edition of GB/T 3091 is more rational, complete and advanced in terms of the systematic structure and the coverage, and thus becomes compatible with relevant international standard, having been suitable for the actual need for the development of the national economy.