The signature file method has widely been advocated as an efficient index scheme to handle new applications demanding a large amount of textual databases. Moreover, it has been recently extended to support multimedia unformatted data. These multimedia data must be rapidly managed for synchronization and presentation, for which parallel database computers have been proposed. In order to achieve good performance, the signature file approach has been required to support parallel database processing. Therefore, in this paper we propose a horizontally divided parallel signature file method (HPSF) using extendible hashing and frame-slicing techniques. In addition, we propose a heuristic processor allocation method so that we may assign signatures into the given number of processors in a uniform way. To show the efficiency of HPSF, we evaluate the performance of HPSF in terms of retrieval time, storage overhead, and insertion time. Finally, we show from the performance results that HPSF outperforms the conventional parallel signature file methods on retrieval performance as well as a dynamic operating measure to combine both retrieval and insertion time.