Abstract: Described here in the paper are the major aspects concerning R＆D of the A-type precision oval welded steel tube by Harbin Steel Tube Plant,including selection of material,production equipment,manufacturing process flow,groove design and in-process quality control,etc.Having been capable of edging out the imported similar foreign product,the said tube has been proven through relevant operation to be up to applicable ASME specification in term of chemical composition,mechanical properties,measured dimensions as well as geometric tolerances.