The invention relates to a fertilizer and a production method and a usage thereof, specifically provides an organic high-protein selenium-rich fertilizer, and the fertilizer is sprayed on the leaf surfaces of fruits and vegetables of root vegetables at different growing periods to achieve the purpose of allowing the fruits and vegetables of the root vegetables to be selenium-rich by utilizing theabsorption and transformation of various elements contained in the organic high-protein selenium-rich fertilizer by the fruits and vegetables of the root vegetables, thus being capable of producing the fruits and vegetables of the selenium-rich root vegetables.