The invention discloses a one-step production process of nylon 5X salt and the prepared high-purity nylon 5X salt. The one-step production process of the nylon 5X salt comprises the steps of carryingout ion exchange adsorption and desorption on a lysine fermentation fluid, obtaining a pure lysine collecting fluid, and after deaminizing, using a nanofiltration membrane for separating part of protein and inorganic salt; utilizing binary acid and lysine for reacting to generate lysine binary acid salt, controlling reaction PH to range from 5 to 6, during a conversion process, directly adding thebinary acid for buffering pH, utilizing a lysine decarboxylase fermentation fluid for one-step converting the lysine binary acid salt into a nylon 5X salt solution, and controlling PH after finishingconversion to be around 7; after filtering and sterilizing through a ceramic membrane, adsorbing impurities, concentrating, crystallizing, extracting and crystallizing a mother liquor through ethyl alcohol after crystallizing, and collecting the nylon 5X salt. The yield and the purity are improved, and the production pollution is reduced.