Objective:To explore the possible functional mechanism for effect of Er-xian Decoction on uterus through quantity analysis of effect of Er-xian Decoction and its compositions on uterus in immature rat.Method:Fifty-four immature female SD rats were randomly divided into nine groups: normal control group（A）

diethylstilbestrol（DES） group（B）

Er-xian Decoction group（C）

Herba Epimedii group（D）

Rhizoma Curculiginis group（E）

Radix Morindae Officinalis group（F）

Radix Angelicae Sinensis group（G）

Cortex Phellodendri group（H）

Rhizoma Anemarrhenae group（I）.After the rats were administrated for six days

serum were got to measure Estradiol（E2）.After bilateral uterus was removed and weighed

paraffin sections

HE staining and immunohistochemical staining were made.Result:The uterus coefficient was increased significantly in Group B

C

D and E（P < 0.05）.The level of E2 in Group B only was increased.It was found diethylstilbestrol（DES） could induce increasing in the height of endometrium epidemic cells and the height of endometrium sreoma cells.Immunohistochemical staining showed that DES caused a decrease in the expression of ERα and ERβ in the uterus of immature rats

but Er-xian Decoction and its kidney-warming composition（Herba Epimedii

Rhizoma Curculiginis） could up-regulate the ERα and ERβ expression.Conclusion: Er-xian Decoction and its kidney-warming composition（Herba Epimedii

Rhizoma Curculiginis） could act as the phytoestrogen by upregulating the expression of ERα and ERβ in the uterus of immature rats.