Abstract: This paper gives four modes' Clenshaw summation formula of Lengendre function. Based on this, the Clenshaw summation formula with two order are derived respectively to calculate the gravity field parameters from the geopotential coefficient expression model. And the precisions in applying the EGM96 and WDM94 to the gravity field of some experimental survey area are both presented which provides some useful reference in the selection of preliminary geopotential model to construct high resolution gravity field of this local area.