Abstract: The present study was conducted to investigate the effect of TBT of environment concentration on emotional behavior of root voles. The experimental group was administrated with 1.0 Ixg/mL of TBT according to the dose of 5 IxL/（g＂ BW） once every 3 days by gavage, and the control group was administrated with the same volume. The experiment period was 45 d. After administration, the open field test, elevated plus maze test and forced swimming test were performed to observe emotional behavior of root voles. The results of open field test showed that there were no significant differences between the males and females of experimental group and those of control group in the comer, central and line-crossing frequency, and the upright frequency of the females of experimental group was significantly higher than that of the females in control group （P〈0.05）.The results of elevated plus maze test showed that there were no significant differences between the males and females of experimental group and those of control group in closed arm time, open arm frequency and head dipping frequency. However, the open arm time of males and females of experimental group were significantly lower than that of males and females of control group （P〈0.05）,and the head dipping frequency of females of experimental group was significantly higher than that of females of control group （/~〈0.05）. The results of forced swimming test showed that there were no significant differences between the males and females of experimental group and those of control group in immobile latency, immobile time and frequency.It was indicated that while TBT of experimental dose could result in mild anxiety of root voles, especially for females, TBT of environment concentration couldnot lead to depression behavior in root voles.