Abstract: Based on the operation circumstances of the Ф76 mm less stand 3-roll mandrel pipe mill line, this very mill is compared with the piercing+cold-rolling (drawing) mill production line in terms of operation cost, finished product rate, investment and operation maintenance, automation level, and energy-saving and environmental friendliness, etc.As a result, it is concluded that when it comes to manufacture of small-sized seamless steel pipes, for producing most of the medium-low pressure boiler pipes, structure-purpose pipes and ordinary fluid transport pipes, etc., which are not so strictly required for demisional accuracy and surface quality, using the less-stand 3-roll mandrel mill as an upgrade mill to replace the piercing+cold-rolling (drawing) mill, in short words, "replacing cold rolling with hot rolling" will bring about remarkable advantages, which is worth spreading up.