Abstract: Global navigation satellite system (GNSS)has been applied more and more widely,however the data record formats provided by different receiver manufacturers are quite different.The Receiver Independent Exchange Format RINEX is internationally used to format the standard import while post-processing data.Ever since it was proposed,RINEX has been optimized and several versions have been developed.Even the identical operation on different RINEX versions of data may look different,in which case the inappropriate definition of data format can lead to fatal errors.This paper introduces several versions of RINEX observation data which are most widely used so far,compares different versions of RINEX files and presents preliminary discussion on data file formats to be used in Chinese BeiDou Navigation Satellite System.