The use of long-exposure photographic plates made the discovery of additional natural satellites possible. The first satellite to be discovered in this manner, Phoebe, was found in 1899 by W.H. Pickering. A reliable model of satellite motion must be constructed with high accurate observations and with data spreading over a period as long as possible. Some old literatures have given the positions of the natural satellites and the reference stars for determining its positions. At that time, the catalogue they used did not contain enough stars, so there were not many catalogue stars on the plates. Because of the unsatisfactory precision of the old catalogue at the epoch and the imprecise measurements on the plate, the positions of the reference stars were not very precise. At present, although we have no plates, we can reduce the positions of the natural satellites from the row data provided in these literatures with modern precise astrometric catalogues, such as PPM and UCAC2. The purpose of this work is to reduce the old observations of Phoebe (Saturn IX), in order to improve its orbit.