The data released by the Shuttle Radar Topography Mission (SRTM) is at two horizontal resolutions; three arc-seconds (90 meter) globally (SRTM90), and one arc-second (30 meter) for the United States (SRTM30), whereas the one arc-second (30 meter) for the other countries had been secreted and used only by USA. The data of SRTM90 are freely available and produced from SRTM30 by using the averaging method. The present study concerned with the accuracy evaluation of the averaging and sampling methods of creating SRTM 90 from SRTM 30. The results obtained verified that SRTM90 produced from the sampling method was better than averaging method.