The invention belongs to the technical field of traditional Chinese medicines, and discloses a preparation method and application of a herba ardisiae japonicae 
alcohol extract. The preparation method comprises the following steps: after 
drying and crushing a herba ardisiae japonicae medicinal material at low temperature, weighing 0.1g of the crushed herba ardisiae japonicae medicinal material, and adding 0.1mL of 
methanol; after carrying out vortex oscillation, carrying out ultrasonic treatment and cooling; then weighing the weight, and supplementing the reduced weight with the 
methanol; uniformly shaking and filtering; taking subsequent filtrate and preserving for later use; weighing a 
bergenin reference substance, and adding the 
methanol to prepare a solution; determining the content of 
bergenin in the herba ardisiae japonicae 
alcohol extract by adopting an ultra-
high performance liquid chromatography. According to the preparation method and the application of the herba ardisiae japonicae 
alcohol extract, the content of the 
bergenin in the herba ardisiae japonicae alcohol extract is 9.88mg / g and accords with quality standards; herba ardisiae japonicae can be used for reducing the quantity of lipid droplets in ST-2 and C3H10 cells which are obtained by inducing 
adipogenesis differentiation, and for inhibiting 
mRNA expression of 
adipogenesis differentiation characterization genes PPARgamma, C / EBPalpha and aP2; 
interventional treatment of the herba ardisiae japonicae can be used for effectively reducing the weight of C57BL / 6 mice fed by 
high fat diet.