Abstract: In the design of the steel pipe for fire water supply, some data are missing, including the steel type, the outside diameter D that is corresponding to the nominal diameter DN, and the pipe wall thickness, etc.Based on related specifications and technical manuals, solution methods and suggestions are proposed to determine the marking method for the steel type, the pipeline standard, and the pipe OD series as well as the calculation method for the pipe wall thickness.It is regarded via the analysis that the design drawing should indicate the standard and material(including the steel type) as required for the steel pipe, the check list of nominal size DN, outside diameter D and nominal W.T.δ of the pipe;in case of computing the water power with some aid software, it must be done to check whether the pipeline standard series and wall thickness as adopted by the software are in compliance with those as designed;it should be foud out if the local supply of the pipes is satisfactory to the design requirements;when the system pressure is 1.20~2.00 MPa, for pipeline with DN ≤ 65 mm and other pipeline sections with working pressure no more than 1.20 MPa, ordinary steel pipes are allowed to be used in order to reduce the project costs.