Complete reaction cross sections, secondary neutron spectra and elastic scattering angular distributions of ~(83)Kr,~(84)Kr,~(85)Kr and ~(86)Kr in the energy region 0.001～20 MeV are calculated, theoritical results are in ENDF/B-6 in prety good accordance with experimenttal data. The natural Kr has 6 stable isotopes: ~(84)Kr, ~(86)Kr, ~(82)Kr, ~(83)Kr, ~(80)Kr and ~(78)Kr, the abundances of which are 57.0%, 17.3%, 11.6%, 11.5%, 2.25% and 0.35%, respectively. However, the four isotopes in the lists of fission product nuclei are ~(84)Kr, ~(86)Kr, ~(83)Kr and ~(85)Kr; however ~(85)Kr is unstable in this work. There are abundant experimental data of σ_(tot) for ~(86)Kr, sufficient experimental data of σ_(tot) for natural element; sufficient experimental data of σ_(n,γ) for ~(83)Kr, ~(84)Kr and natural element. There are no experimental data for any other reaction cross sections, elastic scattering angular distributions, and secondary neutron spectra. All of the experimental data are taken from EXFOR. Th Complete reaction cross sections, secondary neutron spectra and elastic scattering angular distributions of ~ (83) Kr, ~ (84) Kr, ~ (85) Kr and ~ (86) Kr in the energy region 0.001 ~ 20 MeV are calculated, theoritical results The natural Kr has 6 stable isotopes: ~ (84) Kr, ~ (86) Kr, ~ (82) Kr, ~ 83 Kr, ~ 80 Kr and 78 Kr, the abundances of which are 57.0%, 17.3%, 11.6%, 11.5%, 2.25% and 0.35%, respectively. However, the four isotopes in the lists of fission product nuclei are ~ (84 (85) Kr; ~ (85) Kr is unstable in this work. There are abundant experimental data of σ for (86) Kr, sufficient experimental data of σ - (tot) for natural element; sufficient experimental data of σ_ (n, γ) for ~ (83) Kr, ~ (84) Kr and natural element. There are no experimental data for any other reaction cross sections, elastic scattering angular distributions, and secondary neutron spectra. All of the experimental data are t aken from EXFOR. Th