Paralysis of limbs caused by spinal cord injury (SCI) will bring a heavy burden to patients, their families, and society. Our research group has proposed a microelectronic nerve bridge (MENB) method to reconstruct the motor function of SCI patients. The purpose of this paper is to design a MENB stimulator for the reconstruction of the motor function after SCI. The stimulator consists of a main control circuit, a voltage-controlled constant-current driving circuit, a multiplexing circuit, a power management circuit, a Bluetooth communication circuit, a wireless energy-receiving circuit, and stimulating electrodes. The stimulator provides four-channel stimulation signals and receives energy from an external wireless energy transmitting module. The stimulation parameters can be adjusted by the APP through Bluetooth. The size of the stimulator is 3.4x3x1 cm 3 and the weight is 11.7 g. Animal Experimental results show that, the stimulator can activate lower limb muscles and is suitable for the long-term implantable experiments in the SCI rat models.