Abstract: The research aims are that how pitch and duration affect the perception of the neutral tone in standard Chinese and that which one of the two factors is more important. A Psycho-acoustic experiment was conducted. The stimuli of the experiment consisted of 15 groups of disyllabic words, in each of which the pitches and durations of the syllables were controlled. 33 Standard Chinese native speakers participated a forced-choice task to judge if the final syllables of the words they heard carried the neutral tone, i.e., if the syllables were unstressed or normally stressed. The results of the experiment indicate that, (1) the effects of both pitch and duration on the perception of the neutral tone are significant, and the interaction of the two facts is also significant, (2) the effect of pitch is larger than that of duration, (3) pitch influences the perception by the F₀ values of the initial point and of the high point of the pitch curve, and by the pitch contour pattern as well. The results of the experiment have both similarities and dissimilarities to those of the previous acoustic analyses on the neutral tone, and the dissimilarities imply that the acoustic features of the neutral tone that exist in natural speech while do not affect the perception may be phonologically redundant.