A Integrated readout circuit (ROIC)of focal plane arrays for uncooled infrared detector based on microcantilever was proposed. 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 showe 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 (ENC) is below 150e.