The study on time series characteristics of runoff variation in the Dalinghe River Basin has certain scientific significance for the reasonable exploitation of water resources and ecological environment protection. In this paper, with runoff series at 3 hydrometry stations and precipitation series at 15 precipitation stations in the Dalinghe River Basin, the runoff variation characteristics were analyzed with multiple indexes and some methods. The results show that distribution of annual runoff is uneven, mainly in July and August. The inter -annual variation is great with significant difference between wet year and dry year. The tendency of annual runoff reduction is significant, with an abrupt point happening in 1981. The decrease of precipitation and human activities are the key factors influencing on the runoff