Abstract: In order to improve the precision of the altimetry gravity computed by the inverse Stokes formula,the geoidal height of the innermost area is expressed as double cubic polynomial,and a formula to calculate gravity anomaly of this area is derived after the non-singular transformation is introduced.The analysis based on the theoretical model of the geoidal height shows that the accuracy of this formula is quite high.A practical calculation is done based on the geoidal height data with a resolution of 2′×2′,and the results indicate that the contribution of the innermost area to the gravity anomaly recover should not be ignored.The formula derived in this paper could provide theoretical basis for the gravity anomaly recovery with high precision.