[Objective] Studying the ecological ditch interception for reducing nitrogen and phosphorus in water source area of Hanjiang River in order to provide reference and basis for agricultural non-point source pollution control. [Methods] Ditch water of different sections was monitored at different times of rain events to study the intercept effectiveness of nitrogen and phosphorus. [Results] Nitrogen concentration was more greatly influenced by extraneous water from the ditch side than that of phosphorus at the same section. The variance coefficients of TN and NO₃-N concentrations were 19.81%~42.81%, 9.57%~16.73% and 32.14%~42.81% at the upstream, middle and lower section, respectively. The variance coefficients of NH₄⁺-N and TP were 33.33%~88.46% at four sections. Aquatic plant interception decreased the nitrogen and phosphorus concentrations by 9.52%~31.11%. [Conclusion] Ecological ditch can intercept nitrogen obviously. Meanwhile, some sand interception projects should be arranged appropriately for controlling phosphorus loss.