The invention relates to the field of good biotechnology, and particularly relates to a preparation method of egg white powder from dipeptide-pentapeptide. According to the preparation method, fresh egg white is subjected to thermal denaturating treatment and continuous fractional hydrolysis to obtain an egg white oligopeptide solution formed by dipeptide-pentapeptide, wherein the hydrolysis process in the first step is completed by adopting protease with the optimum pH being within the alkaline scope, and the hydrolysis process in the second step is completed by adopting protease with the optimum pH being within the neutral scope; and the egg white powder product is obtained by performing first-step refining for debittering and vacuum concentration with beta-cyclodextrin and second-step refining for deodorization and drying on the egg white oligopeptide solution. The method disclosed by the invention has the advantages of being less in equipment investment and high in product yield; the total protein content of the egg white powder product is higher than 90%, wherein the proportion of the content of dipeptide-pentapeptide in the total protein is higher than 80%, the ash content islower than 6.5%, the average molecular weight is lower than 1000Da, the intestinal absorption and utilization rate is high, the sensitization is low, the instant solubility is excellent, the luster and flavor are fine, and therefore, the egg white powder is especially suitable for the infants, the old and patients in the recovery phase after disease and with gastrointestinal dysfunction to eat, and can be widely applied to the fields of functional food, nutritious food and infant food.