Abstract: Injectable lipid emulsions have been routinely used in patients since 1960s as a nutritional supplement for patients requiring parenteral nutrition. In recent years, lipid injectable emulsions have been extensively studied as a kind of novel drug carrier, also the quality problems of the lipid emulsion attract more and more attentions gradually. Large diameter tail of injectable lipid emulsions as a significant quality control indicator should pay more attention. Regarding to the defect of detecting large diameter tail of lipid injectable emulsions in our country, the purpose of this article is to summarize the techniques of detecting large diameter tail, illustrate the impacts of large lipid droplet on the quality of lipid injectable emulsions, emphasize the importance of detecting large diameter tail in lipid emulsions and provide guidance for researching and developing lipid emulsions in domestic market.