The invention provides a treatment method of lysine fermentation liquor wastewater concentrated liquor. The lysine fermentation liquor wastewater concentrated liquor contains 35-40wt% ammonium sulfate; By virtue of the treatment method, the content of organic substances in the treated lysine fermentation liquor wastewater concentrated liquor is lower than or equal to 2wt%, and the light transmittance is higher than or equal to 88%. The invention further provides a method of producing lysine by fermentation, wherein the method comprises the following steps: inoculating lysine fermented strain into a lysine fermentation culture medium; carrying out fermental cultivation under the condition of feeding a carbon source and a nitrogen source, wherein the nitrogen source contains the lysine fermentation liquor wastewater concentrated liquor treated by the method. According to the invention, the content of the organic substances and light transmittance of the treated lysine fermentation liquor wastewater concentrated liquor are controlled, so that the concentrated liquor can be directly used as an inorganic nitrogen source for producing the lysine, and therefore, not only can fermentation needs of the lysine be satisfied, but also the production cost of the lysine can be lowered.