Abstract: A low power gain control system is proposed in the hearing aid device.Compared with the conventional gain control system in hearing aid,through two MRC blocks,the system achieves the function of automatic and exponential gain control with the reduction of power dissipation.Furthermore,in order to reduce the power in the sound compression region,an energy-saving gain control circuit is also proposed.The system is implemented on Chartered 0.13μm standard CMOS process.The measured results with 1V supply voltage show that: the power of the chip is within 45μW.In addition,the THD is achieved at 0.3% with the output level of 600mV_p-p.