The invention discloses a milk replacer for eliminating allotriophagia of calves and producing white flesh of calves and a preparation method thereof. The milk replacer is made from main materials and a premix, wherein the main materials include corn, soybean meal, flour, vegetable oil and milk powder, and the premix is made from manganese sulfate, sodium selenite, selenium yeast, chromium picolinate, manganese bisglycinate, zinc glycinate, glycine, vitamin A, vitamin E, vitamin D3, niacin, rice hull powder, antioxidant and chitosan. The preparation method of the milk replacer comprises the following steps that the main materials are weighed, and the ingredients except the vegetable oil or the vegetable oil and amylase are mixed to serve as raw materials; the raw materials and water are mixed, soaking is performed to obtain mixed pulp, the vegetable oil is added to the mixed pulp, the premix is added after cooking, and the premix and the amylase are added after stirring or cooking to obtain the milk replacer through saccharification. The milk replacer is high in nutritive value, meanwhile is good in palatability and easy to eat and is also conducive to perfect development of a digestive system and enhancement of disease resistance.