In order to quantitatively characterize the non-uniformity of precipitation in the Huaihe River Basin, the centroid time of annual precipitation was established to generalize the time distribution of precipitation process. The overall pattern and evolution characteristics of precipitation concentration period in the past 55 years was analyzed from three aspects: time domain, space domain and frequency domain. The results show that: (a)the first main period of the centroid time of annual precipitation is 28 years in all selected stations, the mutation mostly happened in the southern area of the upper reaches of Huaihe River around from the late 1970s to the mid or late 1980s, and the time series of centroid time of annual precipitation has an increasing trend but not significant, which indicates that there was a slight backward in most areas of the watershed. (b)The centroid time of annual precipitation has a significant backward trend with the increase of the latitude, and the difference is about 20 days from the south to the north. The change of centroid time of annual precipitation has no correlation with the longitude, which explains that no obvious difference exists between the east and the west. (c)The centroid time of storm and heavy rain is generally later than the other grade of annual precipitation, to which the centroid time of annual precipitation is sensible.