Test circuits for the signal detection and the function electrical stimulation (FES) of neurons have been designed, implemented at first by using discrete devices and characterized off-body. The detecting circuit consisting of three-stage operational amplifiers has a controllable gain up to 105, a -3 dB bandwidth of 30 kHz, and an equivalent input noise of about 9 nV/(开方Hz). The FES circuit consisting of two-stage operational amplifiers has a bandwidth of more than 10 kHz and a variable gain from 20 dB to 60 dB can provide a current of more than 1 mA to a load of 10 kΩ. They are intended to connect with both cuff-type and stag-type microelectrodes. Integrated circuits (IC) for the neural signal process have been designed with features of low voltage and low power. A more biocompatible composite has been synthesized to modify the silicon and related material.