Abstract: Three types of satellite signal imperfection——incompletely suppressed carrier,intermodulation distortion and spurious emissions——and their interference on GNSS signal receiving are studied in this paper.The interference effects are quantitatively analyzed based on signal modeling and analytical computation of the spectral separation coefficient(SSC),the code tracking SSC(CT-SSC) and the effective carrier to noise ratio.Using the signals in GPS L1 and Galileo E1 band,the effects of the noise,the signal processing loss,the external interference,GNSS intrasystem interference and intersystem interference in the presence of different combination of the three types of signal imperfection are calculated.The results show that when the total signal imperfection interference reaches a certain power level,it will have more impacts on signal acquisition,carrier tracking and dada demodulation than intersystem interference.This analysis provides a reference for the specification of the satellite signal quality.