Milk powder is the main nutritional product for infants when they are not breast-fed. The frequent occurrence of melamine, vanillin and other additives has aroused great concern for society. How to more quickly detect and efficiently identify the adverse substances in milk powder is a research hotspot in the field of dairy product safety at home and abroad, which has very important practical significance to ensure the growth and health of infants. Due to a large number of absorption peaks in IR and Raman spectra of starch and vanillin, the overlap region of spectral signals between substrate and additive was wide, and the signal-to-noise ratio was low, which led to serious speak overlap. The more sensitive the instrument is, the more difficult it is to detect and screen. In this study, a non-destructive, rapid and highly sensitive method for determining vanillin as a food additive was established based on X-ray diffraction (XRD). The matrix materials, such as starch and protein of food dairy products, did not have complex diffraction patterns under XRD. Therefore,the detection method of vanillin based on XRD eliminated the background interference of various substrates in food and dairy products.The doping of vanillin could be quickly identified and qualitatively identified by combining the fingerprint characteristics of XRD patterns. The results showed a sharp diffraction peak at 13.03° with good peak shape and high response value in the diffraction pattern after doping vanillin, which would be a characteristic fingerprint peak for rapid detection of vanillin. Compared with gas chromatography and electrophoresis, this method could be more convenient, rapid, accurate in qualitative confirmation to obtain more reliable results and strong applicability while removing matrix influence by direct injection and fine scanning. In this study, the minimum doping amount of vanillin was 202 μg·g-1. The method can be used to rapidly detect vanillin in commercial flavoring foods, and the sensitivity can meet the requirements of recommended limit and excessive application.