In this paper, an automatic syllable detection method namely merging-based syllable detection automaton (MBSDA) is studied and implemented. The MBSDA uses a variety of features including the frame energy, the zero crossing rate and the fundamental frequency to merge similar consecutive frames (one or several frames) into one merged similar segment (MSS). The frames in the same MSS are treated as frames of the same state of a phonetic. These MSSs are passed into a syllable detection automaton (SDA) to give the syllable detection results. In addition, the MBSDA gives the range of syllable number (RNS) of each definite detection segment.