A preparation method for a microemulsion containing a peony extract comprises the following steps: mixing a peony extract with water, hydrolecithin and oil, wherein the weight ratio of the peony extract and water is 1:5 to 1:12, and the concentration of hydrolecithin after mixing is 1 wt% to 50 wt%; and mixing for 10 to 60 min at a shearing rate of 100 to 800 m/sec at 50 to 500 atm. The obtained microemulsion is stable, is convenient in use, and is useful in the preparation of cosmetics and skin care products.