Objective  To explore the role of bone morphogenetic protein/retinoic acid-inducible neural-specific protein 3 (Brinp3) in the differentiation of neural stem cells into neurons induced by valproate (VPA).   Methods  The neural stem cells of rat hippocampi were cultured in vitro. The expression of Brinp3 was detected by Real-time PCR and Western blotting at 24 hour and 48 hour after VPA induced neural stem cells differentiation. Real-time PCR was used to detect the expression of Brinp3 in various tissues of adult rats, as well as in neural stem cells, astrocytes and neurons. After neural stem cells were transfected with Brinp3 small interfering RNA (siRNA) and then induced differentiation for 24 hours, the expression of Brinp3 and neuron-specific markers were detected by Real-time PCR, Western blotting and immunofluorescence technique. All the above experiments included 5 biological repeats.   Results Compared with the control group, the mRNA and protein levels of Brinp3 in the VPA group increased significantly at 24 hour and 48 hour (P<0.05). Brinp3 showed dominant expression in brain tissue, and its expression was lower in astrocytes but higher in neurons (P<0.001). The expression of Brinp3 and neuron-specific markers was significantly inhibited after transfected Brinp3 siRNA into neural stem cells and induced differentiation for 24 hours (P<0.001 and P<0.01, respectively). In addition, the proportion of neurons after differentiation decreased at day 4 (P<0.001).   Conclusion  The upregulation of Brinp3 may mediate the role of VPA promoting the differentiation of neural stem cells into neurons.