The latest research progress of HgCdTe very-long-wavelength infrared focal plane detectors in North China Research Institute of Electro-Optics is reported. The p-on-n heterojunction materials are grown using horizontal liquid phase epitaxy with In doping and vertical liquid phase epitaxy with As doping. Based on wet etching, surface and side passivation, and In bump interconnection process, the first mesa-type HgCdTe very-long-wavelength infrared focal plane device is prepared. At an operating temperature of 60 K, the device has a cut-off wavelength of 14.28 μm, an operability of 94.5%, and an average peak detection rate of 8.98×10¹⁰ cm·Hz^1/2·W^-1.