To study the stability of fal emulsion in all types of AU-in-One nutrient admixtures prepared from on morket fat emnlsions and new MCT/LCTs. Admixtures were prepared from domestic fat emulstions and MCT/LCTs separately with amino acids,dextrose,vitamins, electrolyltes and trace elements. They were stored for one day at 25℃ followed by one day at 25℃ and eight days at 4℃. Admixtures of control group were prepared with fat emulsions and MCT/LCTs of other manufacturers and stored under the same conditions. Particle size and distribution, mass percentage of larger particles to theroretical total iol volume were measured by using light seattering spectrophotometer and coulter multisizer accucomp. Osmolality and pH of the samples were also measured. Stability of the all-in-one admixtures was monitored. The results showe that, compare with the control products, the particle size and distribution of domestic fat emulsions and MCT/LCTs, pH and osmolality of the admixtures remained stable during observation.