Abstract:The sevenparameter space transformation model can be used to obtain local coordinates from observed WGS84 coordinates. What is the generalized corrective coefficient is described. And the generalized corrective coefficients among parameters of shift, rotation angles, and scale in sevenparameter transformation model are calculated. The high correlations among the sevenparameters are testified when the transformation model is applied to a small region, the feasibility of the sevenparameter model and its equivalence to the thereparameter transformation in a small region are demonstrated.