Abstract: Based on the quality characteristics of micro-polluted river water，this study investigated treatment performance by using the composite flow test． The results showed that: Under the hydraulic loading conditions of 10 cm/d and 20 cm/d，the average removal rates of TN in two phases were 36. 34%，28. 53%，respectively; average effluent concentrations of TN were 6. 15 mg /L，12. 45 mg /L; the average removal rates of TP were 90. 86%， 64. 15%; average effluent concentrations of TP were 0. 05 mg /L，0. 42 mg /L． Nitrogen was mainly removed in the first and second zone， and the two parts were filled with rotten wood and zeolites as external carbon source for denitrification process． Phosphorus was removed during the third and fourth zone， the two zones were filled with cement bricks． The cements bricks had a better adorption performance of the low concentration phosphorus，but as time went on，phosphorus removal capacity of the system decreased due to saturated filler，so the reactor need change the filler timely．