OBJECTIVE： To investigate estrogen-like effect of tetrahydroxy stilbene glucoside （TSG） and its effects on the expression of estrogen receptor （ER） in uterus of sexually immature mice. METHODS： Totally 60 sexually immature Kunming mice were randomly divided into normal group， positive control group （estradiol valerate， 0.18 mg/kg）， TSG low-dose and high-dose groups （50， 150 mg/kg）， TSG low-dose and high-dose groups+estradiol valerate groups （same dose as medication alone group）. Normal group was given constant volume of water intragastrically， and administration groups were given relevant medicine 0.2    mL/10 g， once morning and night， for consecutive 5 d. The uterus index and body weight increase of mice in each group were determined and calculated the next day after the last administration. The contents of serum estrogen （E2， LH， FSH） were determined by ELISA. HE staining was used to observe the morphology characteristics of uterus， and uterine tube diameter and endometrial thickness were detected. The expression of ER（ER-α and ER-β） in uterus was detected by immunohistochemical staining. RESULTS： The myometrium of the mice in normal group was parallel and compact， the epithelium of the uterus was columnar， and the expression of ER-α and ER-β was low. The uterine tube diameter， endometrium and epithelium of mice in each administration group increased， thickened or proliferated in varying degrees， and the expression of ER-α and ER-β changed. Compared with normal group， uterus indexes （positive control group， TSG high-dose group， TSG+estradiol valerate groups）， the increase of body weight （positive control group， TSG high-dose groups， TSG low-dose+estradiol valerate group）， uterine tube diameter and endometrial thickness （positive control group， TSG low-dose group， TSG+estradiol valerate groups）， the expression of ER-α （positive control group， TSG+estradiol valerate groups） and the expression of ER-β （postive control group， TSG high-dose+estradiol valerate group）were increased significantly， while serum contents of LH （positive control group， TSG high-dose group） and FSH （TSG low-dose+estradiol valerate group） were decreased significantly （P＜0.05 or P＜0.01）. The uterus index， uterine tube diameter， endometrial thickness and the expression in ER-α and ER-β of TSG+estradiol valerate groups， the increase of body weight and serum content of E2 in TSG low-dose+estradiol valerate group were significantly higher than same TSG dose alone groups （P＜0.05 or P＜0.01）. The uterus index， uterine tube diameter， endometrial thickness and the expression of ER-α and ER-β in TSG groups， uterine tube diameter and the expression of ER-β in TSG+estradiol valerate groups， body weight increase of mice in TSG low-dose group were significantly lower than positive control group， while serum content of LH in TSG+estradiol valerate groups were significantly higher than positive control group （P＜0.05 or P＜0.01）. CONCLUSIONS： TSG can increase uterus indexes and body weight of sexually immature mice to certain extent， regulate estrogen level， increase the diameter of uterine tube and endometrial thickness and up-regulate the expression of ER in the uterus， showing certain estrogen-like effect， which is weaker than that of estradiol valerate. Combined use of them may antagonize the effect of estradiol valerate.