The invention relates to a method for preparing concentration-controllable broiler spleen transfer factor oral solution, which belongs to the technical field of oral products. The method for preparing the concentration-controllable broiler spleen transfer factor oral solution comprises the following processes of: 1) cleaning, namely, cleaning the spleens of broilers and removing fat and capsules;2) crushing, namely, mixing the spleens with water according to the weight ratio of 0.5-3:1, and crushing the spleens by using a waring blender in a way of ensuring the fineness of homogenate; 3) repeated freeze thawing, namely, cooling spleen tissues at -15 to -30 DEG C for more than 10 hours, rapidly dissolving the cooled spleen tissues and repeating the freeze thawing for more than 3 times; and 4) dialysis, namely, placing the freeze thawing-treated spleen tissues into dialysis bags, sealing the dialysis bags, placing the sealed dialysis bags into a container filled with formaldehyde solution-containing normal saline, performing dialysis under magnetic stirring and performing dilution to obtain the clinically applied concentration-controllable broiler spleen transfer factor oral solution. The method has the advantages of simple process, economy, practicability, stable product performance, good clinical effects, wide application range and the like.