Abstract: Elaborated here in the article are the application and manufacturing process characteristics of the largesized,slight-wall metallic pipe. The welding process path and the critical techniques associated with the press-bending formation and continuous roll-bending formation processes are presented. Also pointed out are the technical difficulties associated with such operation procedure as forming,welding,length specifying and weld seam treatment,etc. Furthermore the function and significance of the large-sized,slight-wall metallic pipe for production of the bimetallic pipe are discussed. Based on the case of manufacture and application of the bimetallic hydraulic cylinder,the processing and manufacture methods are elaborated specifically.