The invention relates to a cemented carbide based feed and a preparation method thereof and a cemented carbide based green body and a preparation method thereof. The cemented carbide based feed is used for injection molding of cemented carbide powder and includes the cemented carbide powder and a forming agent. The cemented carbide powder is tungsten-cobalt type cemented carbide powder. The forming agent comprises, by mass, 5-10 parts of paraffin, 5-10 parts of polystyrene, 5-10 parts of high density polyethylene, 5-10 parts of polyethylene glycol and 75-90 parts of polyformaldehyde. The cemented carbide based feed and the cemented carbide based green body comprise the tungsten-cobalt type cemented carbide powder and the forming agents, and the main components of the forming agents are polyformaldehyde, the paraffin, the polystyrene, the high density polyethylene and the polyethylene glycol are added for matching use, the forming agents are used for injection molding of the cemented carbide powder, the disadvantages of poor fluidity and poor machining performance of the cemented carbide based feed caused by large particle size and high hardness of the cemented carbide powder are overcome, and good flowability and processability are achieved.