A grayscale state sequence based feed sorting device, comprising a grayscale sensor, a main controller, a ejection mechanism, a tray, and a guide chute, wherein all materials are placed on the tray and move forward along with the tray, the grayscale sensor acquires a grayscale state sequence of a material and sends the grayscale state sequence to the main controller, and the main controller identifies the grayscale state sequence; the main controller matches the grayscale state sequence with preconfigured standard discharge-allowed attitude data and preconfigured standard discharge-prohibited attitude data; if the grayscale state sequence matches any one piece of the preconfigured standard discharge-allowed attitude data, it indicates that the material is in a target discharge attitude and the material is allowed to pass through the rejection mechanism; and if the grayscale state sequence matches the preconfigured standard discharge-prohibited attitude data, it indicates that the material is in a non-discharge attitude, and the main controller controls the ejection mechanism to return the material to an initial position of the tray; through a falling process in the rejection mechanism and vibration of the tray, the attitude of the returned material is changed and a system performs identification again when the material reaches the rejection mechanism again; if the grayscale state sequence does not match any piece of the standard discharge-allowed attitude data and the standard discharge-prohibited attitude data, the main controller performs a corresponding operation on the material in this condition according to a preconfigured treatment solution, wherein the treatment solution comprises allowing passing through the ejection mechanism, prohibiting passing through the ejection mechanism, and shutdown warning; and along with operation of the feed sorting device, the material finally reaches a discharge station in the target discharge attitude through the guide chute. the main controller matches the grayscale state sequence with preconfigured standard discharge-allowed attitude data and preconfigured standard discharge-prohibited attitude data; if the grayscale state sequence matches any one piece of the preconfigured standard discharge-allowed attitude data, it indicates that the material is in a target discharge attitude and the material is allowed to pass through the rejection mechanism; and if the grayscale state sequence matches the preconfigured standard discharge-prohibited attitude data, it indicates that the material is in a non-discharge attitude, and the main controller controls the ejection mechanism to return the material to an initial position of the tray; through a falling process in the rejection mechanism and vibration of the tray, the attitude of the returned material is changed and a system performs identification again when the material reaches the rejection mechanism again; if the grayscale state sequence does not match any piece of the standard discharge-allowed attitude data and the standard discharge-prohibited attitude data, the main controller performs a corresponding operation on the material in this condition according to a preconfigured treatment solution, wherein the treatment solution comprises allowing passing through the ejection mechanism, prohibiting passing through the ejection mechanism, and shutdown warning; and along with operation of the feed sorting device, the material finally reaches a discharge station in the target discharge attitude through the guide chute.