Investigation has been widely done addressing precipitation processes and runoff changes which is under the combined influences from human activities and climate changes. In this case, based on daily precipitation data from 554 rain stations and monthly runoff data from 370 hydrological stations, Gini coefficient and ANOSIM (Analysis of Similarity) methods are used to investigate the uniformity of precipitation and runoff in space and time. The results indicate that: 1) the uniformity of precipitation at annual scale is increasing from northwest to southeast China. The uniformity change of precipitation is moderate but the uniformity of runoff evidently increased after 1980.2) The Gini coefficient of annual distribution of precipitation is observed to be decreasing in the northeast, northwest and southeast China, which is particularly significant in the upper southwest rivers and in the Yangtze River basin. The Gini coefficient of runoff variations is decreasing generally and it is particularly evident in the Yangtze River basin and in the basins of southeast rivers. After 1980, the Gini coefficient of precipitation and runoff are in adverse patterns in the Yangtze and the Yellow River basins, showing that human activities significantly altered the temporal distribution of runoff. 3) The precipitation and runoff in different regions have similarity in magnitude, frequency, duration and temporal distribution. The uniformity of precipitation in space is decreasing and that of runoff is increasing. Runoff changes should be consistent with precipitation changes. However, human activities such as construction of water reservoirs have greatly altered the runoff distribution which triggered the change of runoff uniformity in space and time. The study will be of great merits in terms of water resources management under influences of climate changes and human activities.