Abstract: With wide application of GNSS in the military and the economy area,a large number of observations recorded every day.These data need to store in the disks and transfer on the internet.In order to reduce data storage space and improve network transmission efficiency,it is necessary to study the compression algorithm for GNSS observations.In this paper,sixty-hex is put forward for digital storage,Recursive differential operation algorithm is used for GNSS observations compression.We have developed the software GnssRAR(V1.0),which can compress GNSS observation data.Experiments show that the compression ratio of GnssRAR can achieved 80% with very good compression.