OBJECTIVE： To investigate the compatibility stability of Fat-soluble vitamin （Ⅱ） /Water-soluble vitamin for injection with common electrolytes. METHODS： Referring to clinical common dose， Fat-soluble vitamin （Ⅱ） for injection /Water-soluble vitamin for injection collective packing [containing Fat-soluble vitamin（Ⅱ） for injection 2 ampoules and Water-soluble for injection 1 ampoule] were respectively mixed with Glucose injection， Potassium chloride injection， Concentrated sodium chloride injection， Sodium bicarbonate injection， Potassium aspartate injection， Potassium aspartate and magnesium aspartate injection， Sodium glycerophosphate injection， Multi-trace elements injection （Ⅱ） to obtain mixture A-H. At room temperature （25 ℃）， these mixtures were investigated in terms of appearance， pH value， osmotic pressure molar concentration and the number of insoluble particles at 0， 1， 2， 3， 4 h. The contents of bacterial endotoxin were tested at 0， 4 h. RESULTS： Within 4 h after mixing， there was no significant change in appearance of those mixtures； pH value of mixture H changed greatly （RSD＝5.13％， n＝5）， and that of mixture D and G increased significantly. The osmotic pressure molar concentration of those mixtures had no significantly change （RSD＜2％，n＝5） and lower than 600 mOsmol/kg. The bacterial endotoxin tests of those mixtures were negative. Two and four hours after mixing， the number of insoluble particles ≥10 μm in mixture B was increased significantly； 2， 3， 4 h after mixing， the number of insoluble particles ≥10 μm in mixture E， F， H were increased significantly； 0 ，1， 2， 3， 4 h after mixing， the number of insoluble particles ≥10 μm in mixture G was increased significantly. There was statistical significance in the number of insoluble particle ≥10 μm in above mixtures compared to mixture A at the same time point （P＜0.05）， but it was in line with the standard of 2015 pharmacopeia. One， two， three and four hours after mixing， the number of insoluble particle ≥10 μm in mixture D was increased significantly， there was statistical significance compared to mixture A at the same time point （P＜0.05）； the number of insoluble particle ≥10 μm in mixture D was beyond prescribed scope of pharmacopeia at 2， 3， 4 h after mixing. Within 4 h after mixing， both the number of insoluble particle ≥10 μm in mixture C and the number of insoluble particle ≥25 μm in edch mixture had no significant change， in accordance with pharmacopeia standard. CONCLUSIONS： Fat-soluble vitamin （Ⅱ）/Water-soluble vitamin for injection is not suitable for mixing with Multi-trace elements injection （Ⅱ）， Sodium glycerophosphate injection or Sodium bicarbonate injection due to great change of pH value and the number of insoluble particles.