Abstract: The interpolation of precise ephemeris is one of the important tasks of GNSS data processing, and its interpolation accuracy also directly affects the positioning accuracy. This paper integrates sliding interpolation theory and Fourier series algorithm, and uses different orders of Fourier series and 9th-order Chebyshev polynomials to fit and interpolate The precision ephemeris of GEO satellite, IGSO satellite, MEO satellite in BDS so as to analyze the interpolation effect of Fourier series interpolation in BDS precision ephemeris interpolation. Experiments show that GEO satellites and IGSO satellites have the highest degree of accuracy when the order of Fourier series is 3, reaching millimeter accuracy. And MEO satellites have the highest accuracy when the order is 4, reaching centimeter accuracy. Compared result shows that 9-order chebyshev fitting in precise ephemeris of GEO satellites and IGSO satellites has higher accuracy, while Fourier series interpolation in that of MEO satellites has higher accuracy.