Abstract: The interaction between speech level, speech rate, and fundamental frequency F₀ was investigated under five different speech styles (loud, normal, soft, fast, and slow) by using four Chinese vowels /a, i, u,y/ with four tones embeded in a frame sentence respectively. Two speakers (one male and one female), who are native of Beijing, were recorded in a listening room. The results show that: 1. The pitch range is moved up and enlarged as increasing the speech level, 2. The lower boundary of pitch range is somewnat moved up as increasing the speech rate, 3. The onset F₀ of the sentence is mainly dependent on tne speech levels, 4. The declination rate is related to both speech level and sentence length, 5. The sentence final F₀ is almost invariant in different speech styles.