In this paper, we present a new analog-front-end system including surface-mounted dry electrode by MEMS dry electrode (MDE) and instrumentation amplifier by chopper-stabilized differential difference amplifier (CHDDA) for physiological signal recording applications. Comparing to traditional electrodes, proposed MDE shows its superior advantages for low electrode skin interface impedance and need not to use electrolytic gel. Moreover, the measured results of the presented CHDDA demonstrated the low power, denoise capability for physiological signal recording. The full AFE system is 4.5*7cm 2 in size, weight 35g and can be operated for 200Hr by 2 AAA batteries. Finally, the actual 4 channel AFE recording of EEG, EOG, ECG and EMG proves the practicability of the proposed system.