Abstract: In this paper the Datum-shift parameters are determined using the map of geoidal undulation based on Rapp's 180×180 solution and the computed values of geoidal undulation with respect to WGS-72 system as well as the map of geoidal undulation with respect to local geodetic coordinate system-1980 of our country.The comparison of the results computed in this paper with the result which has been obtained by using the data of astronomical,geodetic,gravimetric and Doppler observations in our country manifest that the both results are consistent with an accuracy of ±10^m.