The invention relates to an auxiliary instrument for gynecological and obstetric surgery. The auxiliary instrument comprise an obstetric forceps body, a pressure control unit and a force application unit, wherein the obstetric forceps body comprises two forceps bodies which are arranged in a crossed mode, each forceps body comprises a forceps head, a forceps arm and a forceps handle, and the forceps head, the forceps arm and the forceps handle are connected in sequence; the outer surfaces of the forceps heads are coated with silica gel sleeves, the two forceps arms are connected in a swingingmode, and containing cavities are formed in the forceps bodies and extend to the forceps handles from the forceps heads in the length direction of the forceps bodies; the pressure control unit comprises a miniature pressure sensor, a signal converter and a digital display which are connected in sequence, the miniature pressure sensor and the signal converter are respectively contained in the corresponding containing cavity, and the signal converter receives the pressure signal and transmits the pressure signal to the digital display to be displayed; the force application unit comprises a pneumatic pull rod, a force application controller and a handle, the pneumatic pull rod is arranged between the two forceps handles, and the output end of the force application controller is connected withthe input end of the pneumatic pull rod. The gynecological surgery auxiliary instrument can ensure the safety of fetuses and lying-in women, and is high in safety.