Abstract: OBJECTIVE To investigate the effect of thickening agents on the stability of propofol emulsion injection.METHODS The influence of three kinds of thickening agents including sodium carboxymethyl cellulose, hyaluronic acid, carboxymethyl chitosan amount on the stability of propofol emulsion injection were investigated by rapid stability analysis instrument LUMiSizer, combined with standing observation, centrifugal precipitation, average particle size, and Zeta potential. RESULTS Sodium carboxymethyl cellulose and carboxymethyl chitosan were easy to cause flocculation and sediment of emulsion, but good inhibition effect of sedimentation with 0.02%–0.1% of hyaluronic acid. CONCLUSION Hyaluronic acid can reduce the sedimentation rate of components in the emulsion by forming a reticular structure, and significantly improves the stability of propofol emulsion injection.