Long wave infrared detectors have the characteristics of large dark current,difficult to control dark current fluctuations.The larger the area of the image element,the more difficult it is to control the dark current.In this paper,a readout circuit is designed for a long wave detector with a super pixel area.By splitting the super pixel into several sub pixels and using the sub pixels equivalent integration,the problems of large dark current in super pixel of long wave detector and difficult to control dark current can be effectively solved.The circuit designed in this paper splits 96μm×96μmarea pixel into 3×3 sub pixels,and the signal is accumulated and output after the sub pixel integration.The circuit also has multiple integral capacitances and by pass of each sub pixel function,blind pixel replacement and so on.The functional and performance simulation results and test results of the circuit are also given in the paper.