Abstract: A new approach named the mirror surface projection method is proposed,may be utilized to determinate the orbit of a GEO satellite precisely.It sets the orbital plane of the GEO satellite as the symmetry plane(or the mirror surface),the original observation stations as the virtual observation stations by projection;the distances from the original stations to the GEO satellite are used to constitute the virtual observation values.The simulating computations indicate that the effect of the new method obviously excel that of the existing method in the precision of the orbit determination.