This paper aims to determine the observation time of Shi Shen's star catalogue. We first considered the basic data of the catalogue in general and analyzed possible systematic errors of the observation. Then we used the data of the determinative stars of 28 lunar lodges in the catalogue as a representative sample of data to determine the observation time by means of Fourier analysis. We conclude that it was observed at the end of the Western Han dynasty at 60 ± 30 years B.C. We also discuss the historical background of that time which enlightens and illustrates our conclusion.