A readout integrated circuit (ROIC) of focal plane arrays for uncooled infrared detectors based on microcantilever was designed. The ROIC was optimized to reduce noise based on noise modeling and analysis. A prototype of 16×16 ROIC was designed and fabricated by 035μm CMOS technology. The measurement results show that the power dissipation is 165mW for a 5V supply voltage at 50Hz frame rate, the linearity is 992% at typical modes, the uniformity is larger than 97% and the equivalent noise charge (NEC) is below 150e.