The machine is a specially used for boring long and thin pipes. It adopts the processing mode of workpiece rotation (passing through the spindle hole of headstock) and cutting tool bar is fixed and only for feed motion. When boring, the cutting fluid is supplied by the oil pressure head, and the cutting chips are discharged forward. The cutting tool feed adopts AC servo drive system to realize stepless speed regulation. Headstock adopts multi-stage gear speed change, with a wide speed range. Mechanical locking device is used for clamping of the oil pressure head and workpiece.