The aim of this study is to develop a self microemulsion drug delivery system for phytosterols to improve the solubility and bioavailability. The results showed that the formulation of phytosterol self-microemulsion is: lemon essential oil in oil phase, polyoxyethylene hydrogenated castor oil 40 and Tween 60 in emulsifier, polyethylene glycol 400 in co-emulsifier, Km = 7:3, Kp = 3:1, Ke = 50%. The drug loading of phytosterol self-microemulsion prepared by this method was 87.22 mg/g, encapsulation efficiency was 89.65%, particle size was 48.85nm, potential was -12.863mV. In vitro release experiment showed that the release of phytosterols in microemulsion was more than 90%, and the release curve was in accordance with the first-order kinetics equation. The pharmacokinetic analysis of PSSM synthesized by this method shows that PSSM can increase the bioavailability of PS more than three times, so it is necessary to do more in-depth research on the self-microemulsion delivery system of phytosterols.