It is simple in technology and reliable in system for the seawater desulphurization system in thermal power plant.The efficiency of this desulphurization system will be over 90 %.The system applies to the power plant near sea.Medium or low sulphur coal with the sulphur content less than 1.5% shall be used because its discharge index doesn't overtake the present effluent standard.Analysis and research on the operation of seawater desulphurization system in thermal power plant has been presented in this paper.The desulphurization technology is worth extending and applying to power plants fired with medium or low sulphur coal.