Abstract: Objective To investigate whether sulforaphane (SF) protects motor neurons via inducing phase Ⅱ enzymes. Methods The SD rat pups spinal cord organotypic cultures were divided into three groups at random: control, 100?mol/L THA group, 10?mol/L SF plus 100?mol/L THA group. The number of motor neurons was assessed by immunohistochemistry, and the expression of phase Ⅱ enzymes were assayed with western blot. Results At the end of 3 weeks, the motor neurons number in the group treated with THA was less than the control group (P<0.05, n=10-15). However, the motor neurons number in the group treated with SF plus THA was more than group treated with THA at the end of 3 weeks (P<0.05, n=10-15). Meanwhile, the phase Ⅱ enzymes (NQO-1 and HO-1) in the group treated with SF plus THA expressed more than group treated with THA only (P<0.05, n=3). Conclusions SF could prevent motor neuron death caused by THA toxicity via inducing the expression of phase Ⅱ enzymes.