OBJECTIVE： To investigate the effects of different concentrations of potassium ion （K+） on the stability of total parenteral nutrition（TPN）， and to provide reference for clinical drug use. METHODS： TPN prescriptions containing different concentrations of different concentrations of K+（29.13， 43.23， 50.16， 57.02， 70.53， 83.75 mmol/L， group 1-group 6）were designed. TPN infusion bag was prepared according to sterile operation procedure. The appearance， pH value， insoluble particle， particle size and granularity （polydispersity coefficient） of lipid emulsion at room temperature （25 ℃） were investigated after placing for 0， 8， 24， 48 h. The effects of different concentrations of K+ on the stability of TPN was investigated. RESULTS： There was no observable alteration in appearance color， stratification， flocculation and wall-hanging of 6 groups of TPN at 0， 8， 24， 48 h after preparation. pH value for all groups were between （6.17±0.01）-（6.49±0.01） within 48 h at room temperature. The insoluble particles of group 1-3 within 48 h were in line with the regulations stated in 2015 edition of Chinese Pharmacopeia （part Ⅳ）. However， insoluble particles≥10 μm in group 4 was 14 grains/mL after placing 48 h， insoluble particles≥25 μm in group 5 and group 6 were 3 grains/mL after preparation， which were not in line with the requirements of 2015 edition of Chinese Pharmacopeia （part Ⅳ）. The particle sizes of lipid emulsion of 6 groups were between （236.7±6.8）-（267.2±11.6） nm； polydispersity coefficient for all groups were 0.027-0.099. With the increase of K+ concentration， there is a certain difference between pH value （P＝0.001） and granularity （P＝0.043） of 6 groups； the change did not satisfy with any kind of straight line or curve trend. CONCLUSIONS： Placing 48 h at room temperature， in prescriptions of K+ concentration ≤50 mmol/L， appearance， pH value， insoluble particle and particle size of lipid emulsion are all in line with related regulations. In prescriptions of K+ concentration＞50 mmol/L. The appearance， pH value and particle size of lipid emulsion are all in line with related regulations， but insoluble particle is not in line with related regulations and should be used cautiously in clinic.