Integrated circuits of deep submicron (DSM) CMOS technology are advantageous in volume density, power consumption and thermal noise for multichannel particle detection systems, but there are challenges in the front-end circuit design. In this paper, we present a 0.18 μm CMOS front-end readout circuit for low noise CdZnTe detectors in tens of pF capacitance. Solutions to the noise and gate leak problems in DSM technologies are discussed in detail. A prototype chip was designed, with a charge sensitive preamplifier, a 4^th order semi-Gaussian shaper and several output drivers. Test results show that the chip has an equivalent noise charge of 164 e, without connecting it to a detector, with an integral nonlinearity of <0.21% and differential nonlinearity of < 3.75%.