The utility model provides a feedwater medicine system of nuclear power station, it includes: the water -feeding pump, the water -feeding pump is equipped with low discharge reflux pipeline, be provided with with the pencil line on the low discharge reflux pipeline, fluid in the low discharge reflux pipeline through the configuration with add the mixed postinjection of chemical agent of pencil on -line the entry pipeline of water -feeding pump to reach the low discharge backward flow and adjust quality of water, the jet pump, the jet pump sets up on adding the pencil line, through the configuration be used for with the chemical agent that adds the pencil on -line with fluid mixing in the low discharge reflux pipeline. The feedwater medicine system of nuclear power station that this embodiment provided has set up on the low discharge reflux pipeline of water -feeding pump with the pencil line to the adoption has the jet pump of the active characteristics of non -, realizes feedwater and chemical agent's mixture, has improved system's reliability of operation and economic nature.