Abstract: Described here in the article discloses is a method for selection of the welded mother tube type for improving surface roughness of the cold-drawn precision tube. The pro and post deformation surface toughness of the welded mother tubes with different sizes is measured,the increase rate of the pro and post drawing-caused deformation middlediameter to wall thickness ratio of the said mother tube is calculated,and the relationship between the said increase rate and the said surface toughness is analyzed,of which all the results are verified via actual production activities. Thanks to the above mentioned method,the proper process can be prepared before the production via relevant theoretic calculation so as to avoid any waste in the production.