Abstract: The microbial-dominated denitrification process is the main way to absorb the loss of non-point source nitrogen in flooded sediments. At present,there are plentiful researches on the influence of environmental factors on the denitrification process,but the law of denitrification under the influence of periphyton is still unclear. Through the submerged sediment culture experiment,the nitrogen denitrification rate,and total of 17 indicators of the overlying water-peripheral organisms-sediment system influencing denitrification process are measured,and the PLSR model is used to explore the influence of various factors on the denitrification and absorption of non-point source nitrogen in the sediment,and to find out the main control factor and avoid the problem of collinearity between factors. The results show that the pH,NH4+-N,NO3--N,DOC in the overlying water and the CHI in the periphyton are the main influencing factors in the denitrification process of the sediment. More attention is paid to the research on periphyton. The water-soil interface can demonstrate the mechanism of nitrogen denitrification loss process and provide a theoretical basis for non-point source pollution control.