The nutritive salt analyzer is our key research and development project achievement, jointly developed by The Chinese Academy of Sciences and Frankstar. The instrument completely simulates manual operation, and only one instrument can simultaneously complete the in-situ on-line monitoring of five kinds of nutritive salt (No2-N nitrite, NO3-N nitrate, PO4-P phosphate, NH4-N ammonia nitrogen, SiO3-Si silicate) with high quality. Equipped with a handheld terminal,simplified setting process, and convenient operation, It can meet the needs of buoy, ship and other field debugging.