Microfluidic chip for detecting nitrogen and phosphorus contents in water body and detection method

The invention provides a microfluidic chip for detecting nitrogen and phosphorus contents in a water body and a detection method. The microfluidic chip comprises an upper layer, a diaphragm layer, a lower layer and a supporting layer which are sequentially arranged from top to bottom, and the upper layer, the diaphragm layer, the lower layer and the supporting layer are all circular, wherein the upper layer is provided with an upper-layer reagent injection port, N upper-layer mixing cavities, N upper-layer digestion cavities and N upper-layer color developing cavities; the lower layer is provided with a lower-layer reagent injection port, N lower-layer mixing cavities, N lower-layer digestion cavities, N lower-layer color developing cavities and a reference tank; and the upper-layer reagent injection port and the lower-layer reagent injection port coincide in position and are separated by the diaphragm layer. The invention also provides a detection method for detecting nitrogen and phosphorus contents in a wa