Abstract: his paper introduces direct measurement of the antenna G/ T performance in three data channels by using the sun as a radio source after the Chinese Landsat Ground receiving station is upgraded.For fixed-turned data channels, antenna G/ T～α(antenna elevation angle) performance curves of the Landsat-5 down link frequency arc measured. For tuned data channels. G/ T the performance characteristics of Landsat-6. JERS-1. ERS-1. SPOT and ZY-1 Satellites down link frequencies are measured in the case of a equal to 5°and 30°.Finally the Error analysis is presented.