The utility model discloses a high stable lathe arm, including arm device and stabilising arrangement, the arm device includes fixing base, bottom plate, montant, dwang, connecting block, flexible pipe and chuck, the inside of fixing base is equipped with the motor, the connection dwang is rotated in the pivot that the motor passes through on the bearing, the bottom plate is connected at the top of fixing base, the montant is connected at the left side top of bottom plate, the montant passes through the connecting block and connects flexible pipe, the chuck is connected on the right side of flexible pipe, stabilising arrangement is connected to the bottom of arm device. Inside spring beam the reciprocating in the cavity of this kind of equipment utilization stabilising arrangement makes the arm device more stable, has designed the fixed cover of a correspondence simultaneously in the bottom on chassis, and fixed cover inserts expansion bolts through four round holes and is fixed in equipment or ground, utilizes the inside rubber circle and the cyclic annular square cooperation of borduring of square cavity of fixed cover, is convenient for remove the stability and the flexibility that have improved equipment.