Abstract: A method for evaluating nitrogen bio-removal capacity in water based on functional traits of benthic macroinvertebrates, comprising: S1, constructing an evaluation table for the nitrogen bio-removal capacity in water, and S2, collecting the benthic macroinvertebrates in the water to be evaluated, calculating the final functional trait evaluation scores of the benthic macroinvertebrates based on modalities that are strongly correlated with nitrogen bio-removal rate of water indicating the nitrogen bio-removal capacity in water, and then determining corresponding grade based on the evaluation table. The present application requires only the collection and identification of benthic macroinvertebrates from water to obtain the functional trait evaluation result, enabling the determination of the nitrogen bio-removal rate for the water by using the pre-constructed assessment table.