With　increasing　requirements　for　the　accuracy　of　Pendulous　Integrating　Gyroscopic　Accelerometer　(PIGA),　developing　effective　methods　that　can　accurately　calibrate　nonlinear　error　parameters　of　PIGA　is　a　necessity.　In　this　paper,　the　symmetric　position　calibration　method　is　proposed　to　calibrate　the　main　nonlinear　error　coefficients　of　PIGA　within　integer　precession　periods　on　the　centrifuge.　Firstly,　coordinate　systems　are　established,　and　specific　forces,　as　well　as　angular　velocities　of　PIGA,　are　deduced.　Then,　the　complete　error　calibration　model　of　PIGA,　including　the　high-order　error　terms,　is　established.　Calibration　methods　in　symmetric　positions　are　proposed,　while　the　closure　errors　are　restrained　by　the　reasonable　design　of　the　test　time.　The　centrifuge　experiments　show　that　the　influence　of　misalignments　could　be　restrained　by　the　proposed　calibration　method,　but　the　angular　velocity　of　the　main　axis　should　be　monitored.　Thus,　the　impact　of　centrifuge　errors　on　the　measurement　accuracy　of　PIGA　is　effectively　suppressed,　thereby　reducing　output　uncertainty　of　PIGA　to　10(-6　)rad/s.　The　simulation　results　show　that　the　order　of　calibration　uncertainty　of　PIGA＇s　second-order　error　parameter　is　decreased　from　10(-6)　to　10(-7)　and　the　order　of　calibration　uncertainty　of　other　nonlinear　error　term　coefficients　is　lowered　to　less　than　10-6.　Finally,　the　calibration　accuracy　of　PIGA　reaches　1　x　10(-7)g/g.