Abstract: In order to demonstrate the naturalness of speech in text-to-speech, the basic work is to have a study on the pitch of spontaneous speech. Based on the 973 telephone corpus, the pitch ranges and pitch registers of 1084 intonation phrases are analyzed. It is found that intonation phrases can be classified according to their ranges and scales, and this is related to their positions in dialogue exchange. Compared to read speech, the pitch patterns in dialogue are more variable.