Abstract: Based on the current situation of domestic production of small-sized seamless steel pipes, and relevant existing problems, the actual application of the Φ76 mm less stand 3-roll mandrel mill to produce small-sized seamless steel pipes is detailed here in the paper. The operation practice with the said mill leads to such a conclusion that when it comes to producing small-sized seamless steel pipes, the mandrel mill is in possession of such advantages as low initial investment, high production flexibility, easy operation, and suitability for small lot order and frequent size-change, being an ideal mill type for production of small-sized seamless steel pipes.