This paper presents the recent progress in the research of high operating temperature （HOT） mid-wavelength infrared （MWIR） HgCdTe focal plane arrays （FPAs） at Kunming Institute of Physics. By optimizing the structural parameters of mid-wavelength infrared HgCdTe detectors， a 640×512@15 μm mid-wavelength infrared focal plane array （FPA） was fabricated based on high-quality in situ indium-doped HgCdTe film grown by liquid phase epitaxy （LPE） using arsenic-ion-implanted p-on-n planar junction device technology. The spectral response， device dark current， noise equivalent temperature difference （NETD）， operability， and the distribution of defective pixels of the prepared p-on-n chip arrays at various operating temperatures were tested using a variable temperature Dewar. The test results demonstrate that the detector has the ability to operate at temperatures above 180 K.