An analog IC applied to ECG monitoring devices has been presented in this paper. The system consists of instrumentation amplifier with driven-right-leg circuit, 2nd active low pass filter, the second amplify stage, high power supply rejection ratio (PSRR) low dropout voltage regulator (LDO) and leadoff monitoring circuit. This chip has included all necessary functions for industrial applications. And it has high common mode rejection and power supply rejection performance. The design is fabricated with SMIC 0.18 μm CMOS process. And the measured results have demonstrated this chip’s functionalities. The gain of the mid-band is 51 dB. And the CMRR and PSRR achieve 75 dB and 90 dB. The IC consumes 190 μA currents with 2.9~5.5 V supply voltage.