The utility model relates to a magnetic base for a numerical control machine tool dynamic testing sensor. The magnet base comprises a magnet base body, a non-magnetic tube sleeve and a rotating magnet. One end of the non-magnetic tube sleeve is fixed on the magnetic base body, and an axial hole is formed in the other end of the non-magnetic tube sleeve in the radial direction. The rotating magnet is movably positioned in the axial hole in the non-magnetic tube sleeve through a radial guiding shaft, and the end plane, axially perpendicular to the non-magnetic tube sleeve, of the magnetic base body and the end plane, axially perpendicular to the non-magnetic tube sleeve, of the rotating magnet are working planes. A cavity in which the sensor is installed is formed by the non-magnetic tube sleeve and the magnetic base body. The attraction force of the magnetic base body can be changed by reversely rotating the rotating magnet by 180 degrees, and two states of attraction position or position reliving can be achieved. The magnetic base for the numerical control machine tool dynamic testing sensor has the advantages of being compact in structure and reasonable in magnetic path design, position and position relieving are carried out conveniently, the positioning problem of the sensor is solved, the protection space for the sensor is provided, and the damage to the sensor during testing is effectively avoided.