In this paper, a Monte Carlo simulation model based on atmosphere model, cosmic ray model and geomagnetic field model has been developed for the near space atmospheric neutron environment. The neutron distributions induced by cosmic rays and solar particles have been calculated separately. What is more, the influence of cutoff rigidity to neutron flux has been analyzed. By comparing with ARM model, we can draw the conclusion that our model is credible and excellence in calculating neutron flux induced by solar particles. The model could be applied in many fields, such as evaluating single event effects of microelectronics and analyzing radiation dose received by the air crew.