The p-on-n structure doped with As implantation has the advantages of low dark current，high R₀A product， and long minority carrier lifetime，which is an important trend in the development of long-wavelength and very long-wavelength HgCdTe infrared focal plane detectors. P-on-n LWIR and VLWIR HgCdTe infrared focal plane detectors with cut-off wavelength of 9.5 μm and 10.1μm at 77 K and 14.97 μm at 71 K fabricated by Kunming Institute of Physics are introduced.Test and analyze performance parameters such as the responsivity， NETD， dark current and R₀A of the detectors. The test results show that the operability of the detectors is between 99.78% and 99.9%，and the NETD of the detectors is less than 21 mK. The effective fabrication of p-on-n LWIR and VLWIR HgCdTe infrared focal plane detectors is realized.