Objective To investigate the relationship between thyroid hormone receptor β1 (TRβ1) and atypical meningioma, and to investigate the role of TRβ1 in atypical meningioma. Methods Real-time PCR and immunohistochemistry were used to measure the mRNA and protein expression of TRβ1 in benign meningioma and atypical meningioma. In addition, primary meningioma cells were cultured in vitro, and MTT assay was used to investigate the effect of TRβ1 on atypical meningioma cells. Results The mRNA expression of TRβ1 in atypical meningioma was lower than that in benign meningioma (P>0.05). Immunohistochemistry results showed that the mean number of TRβ1+ cells in atypical meningioma was significantly lower than that in benign meningioma (40.75 cells/mm² vs 93 cells/mm², P<0.05). In the assay in vitro, T3 effectively inhibited the proliferation of atypical meningioma cells, reducing MTT absorbance from 0.24±0.028 in the control group to 0.17±0.008 in the treated group at a concentration of 20 ng/ml (P<0.05), which suggested that T3 had a marked inhibitory effect on the proliferation. When the expression of TRβ1 protein was down-regulated by small interfering RNA, the inhibitory effect of T3 on atypical meningioma cells was effectively attenuated. Conclusions The expression of TRβ1 in atypical meningioma is lower than that in benign meningioma. And TRβ1 can effectively inhibit the proliferation of atypical meningioma cells after being activated by T3. This suggests that TRβ1 may play an important role in the development and progression of atypical meningioma.