The product is based on wet chemical photometry analysis. It adopts peristaltic pump precise metering, closed-loop rapid reaction flow path, and single LED light source composite detection design. It is an independently developed multi-parameter integrated seawater nutrient salt analyzer that can sequentially measure four nutrient salt parameters in seawater: ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), and phosphate (PO4-P). It is small in size, low in power consumption, easy to carry and deploy, and can operate in complex and extreme environments of marine wet salt. The monitoring data is accurate, reliable, and available, and is suitable for in-situ monitoring of marine and estuary water quality.