Abstract: This paper analyzes the Compass observations through the zero baseline experiments,including the time series of signal to noise ratio(SNR),multipath and the Compass single-difference residuals,which change with the elevation angles.Compared with GPS observations,the Compass signals have some differences.For example,GPS L1 signal is stronger than L2 signal,while the Compass B2 signal is stronger than B1.The Compass carrier phase single-difference residuals changes with the elevation can be used to refinement the elevation-weighting method and SNR-weighting method.The experimental results show that the accuracy of Compass observations are reliable,which can be used in high-precision navigation and positioning,meanwhile,the quality analysis of the Compass observations can provide the basis for building stochastic model.