Due to the characteristics of tunable bandgap, large electron effective mass, and low Auger recombination rate, type-II superlattices have unique advantages in long-wave and very long-wave infrared detection. The research progress in the preparation of long-wave superlattice detectors is introduced, including band structure design, surface defects control, periodic structure control and surface passivation. Finally, a 320×256 long-wave superlattice focal plane array and its test performance are reported. The results show that at an operating temperature of 77 K, the cut-off wavelength of the array is 9.6 μm, the average peak detection rate D* is 7×10¹⁰ cm·Hz^1/2/W, the noise equivalent temperature difference (NETD) is 34 mK, and the response non-uniformity is 7%.