It is very difficult to be measured accurately for the micro corrosion current of multi-electrode array. This paper designs a measurement method based on multi-channel electronic switching real-time comparison measurement to obtain high precision measurement using the STM32 single chip microcomputer technology. Choosing the operational amplifier with small bias current order of pA, The impact of offset voltage is eliminated by applying automatic voltage regulator of ADC, floating and connecting ground of switch. The switch were connected to ground and corrosion electrode in turn to eliminate the interference of low-frequency current noise and improve micro-current measurement accuracy. The experimental results show that this method for corrosion electrode current can arrive at the accuracy of 0.1uA.