Wuhan Guide Infrared Co., Ltd. has successfully developed a 1280×1024 large-format HgCdTe mid-wave infrared focal plane detector with a pixel size of 12 μm×12 μm. On the basis of optimizing and improving the performance of materials, the key technologies such as passivation of small pixel, preparation of high-density and small-size indium column, and high-precision and large area array reverse welding have been broken through. The 1280×1024@12 μm mid-wave HgCdTe infrared focal plane chips and components were successfully fabricated. The default pixel rate is less than 0.5%, and the non-uniformity of response rate is less than 5%. The average noise equivalent temperature difference (NETD)of F2 detector is 15 mK, and the average peak detection rate is 6×10¹¹ cm·Hzsup>1/2·W^-1. The average NETD of F4 detector is 18.5 mK, and the average peak detection rate is 1.2×10¹² cm·Hzsup>1/2·W^-1. In addition, a method for testing unstable pixels is proposed. By analyzing the image data after two-point correction and comparing the median value of the module with the spatial noise, the detection and correction of unstable pixels in infrared image are completed. After correction, the infrared imaging quality is good, and the performance of the device does not decrease obviously at 120 K.