[Objective] To observe the effect of serum containing Carapax et Plastrum Testudinis (CPT) in inducing the differentiation of mesenchymal stem cells (MSC) of adult rats into neurons. [Methods] The fifth generation of MSC were induced by the serum containing CPT (sero-CPT) and the expressions of neurofilament (NF) protein and glial fibrillary acidic protein (GFAP), the marks of neuron-like cells were detected by immunohistochemical method. [Results] The expression of NF protein was positive after the stimulation of sero-CPT and the expression reached the peak 12 hours after induction. [Conclusion] Sero-CPT can induce the differentiation of MSC into neurons in vitro.