With increasing demand of medical health, continuous monitoring of important physiological parameters of patients with chronic diseases may provide crucial information for clinical assessment. A wearable system for multi-channel physiological signal acquisitions is proposed in this paper. According to the characteristics of weak signal and low signal-to-noise ratio, the proposed system designed the protection circuit, impedance matching circuit, the signal conditioning amplifier circuit, ADC and the main control circuit for improving common-mode rejection ratio and reducing average power consumption of the system. Meanwhile, the channel structure, gain and bandwidth of the system can be set adjusted for the requirements of different physiological signals. The results show that the system possesses low-power consumption, high common-mode rejection ratio and voltage gain. The signal can be stored and transmitted to the terminal and displayed in real time. Therefore, the proposed signal acquisition system can be applied in the wearable medical field.