When -1.4 V bias and 3.5 nW 633 nm laser radiation are applied,the GaAs / InGaAs quantum dot-in-well photodetector can get 8.9×10-9 A response current and the current responsivity is 2.54 A/W.Its quantum efficiency is above 90%.Based on the photoelectric characteristics of the InGaAs/GaAs Quantum dot Photodetector,a stable bias,high inject efficiency and low noise CTIA readout circuit has been designed,which applies correlated double sampling （CDS） to the output of the CTIA circuit.Experiment results show that the readout circuit works well and the voltage responsivity can reach 7.14×107 V/W when the 50 μm×50 μm pixel device is biased with -2.5 V and radiated with 3.5 nW laser power.