Abstract: Atmospheric neutron is one of the major radioactive particles in the near space which seriously threatens the safety of spacecraft at this region. In this paper, the neutron spectra at different periods, longitudes, latitudes, altitudes are studied. For different energies of isotropic incident neutrons, the upset cross section of the static random access memory (SRAM) is calculated. The single event upset (SEU) rate for SRAM during the flight between any two places in the near space is obtained. All calculation results are verified.