[Objective] The effect of inoculation effective microorganisms (EM) to shrimp ponds of seawater was studied,with analysis of affecting factors including NH3-N,NO2-N,dissolved oxygen (DO),COD,sulfide and pH. [Method] 11.25 L/hm2 EM was sprayed to shrimp ponds once after or at an interval of half month. [Result] Inoculation EM could significantly decrease NH3-N,NO2-N,sulfide,and COD of the experimental groups,increase dissolved oxygen (DO) and stabilize pH of the experimental groups. [Conclusion] Water qualit...