A servomotor comprising: a control circuit, an electric motor, a harmonic drive and a sensor; the control circuit being electrically connected to the electric motor, and configured to output signals to control the electric motor to rotate; the harmonic drive comprising an outer casing, a wave generator, a flex spline and a circular spline that are arranged within the outer casing, the electric motor being arranged at one end of the outer casing, the wave generator being driven by the electric motor, the flex spline being sleeved on an exterior of the wave generator, the circular spline being fixed within the outer casing, the flex spline being located within the circular spline and engaging with the circular spline; the flex spline being connected with an output member that is configured to output power, and a post arranged along a rotation axis of the output member; and the sensor being arranged within the outer casing and configured to detect angular displacement of the post; characterised in that the harmonic drive further comprises a flex spline pressing member and a bearing inner ring, the flex spline pressing member comprises a position limiting portion and a protruding portion, the flex spline defines a first through hole in a bottom thereof, the bearing inner ring defines a second through hole, the protruding portion of the flex spline pressing member passes through the first through hole and the second through hole in sequence, and the flex spline is arranged between the position limiting portion of flex spline pressing member and the bearing inner ring, and wherein the output member, the bearing inner ring, the flex spline and the flex spline pressing member are fixed together. a control circuit, an electric motor, a harmonic drive and a sensor; the control circuit being electrically connected to the electric motor, and configured to output signals to control the electric motor to rotate; the harmonic drive comprising an outer casing, a wave generator, a flex spline and a circular spline that are arranged within the outer casing, the electric motor being arranged at one end of the outer casing, the wave generator being driven by the electric motor, the flex spline being sleeved on an exterior of the wave generator, the circular spline being fixed within the outer casing, the flex spline being located within the circular spline and engaging with the circular spline; the flex spline being connected with an output member that is configured to output power, and a post arranged along a rotation axis of the output member; and the sensor being arranged within the outer casing and configured to detect angular displacement of the post; characterised in that the harmonic drive further comprises a flex spline pressing member and a bearing inner ring, the flex spline pressing member comprises a position limiting portion and a protruding portion, the flex spline defines a first through hole in a bottom thereof, the bearing inner ring defines a second through hole, the protruding portion of the flex spline pressing member passes through the first through hole and the second through hole in sequence, and the flex spline is arranged between the position limiting portion of flex spline pressing member and the bearing inner ring, and wherein the output member, the bearing inner ring, the flex spline and the flex spline pressing member are fixed together.