Abstract: Several typical low altitude orbits' radiation belt particle environment have been computed by using IGRF2000 and compared with those of using IGRF1970. The results show that the orbit integral flax's variation for protons with energy greater than 0.1 MeV reaches two order of magnitude for some inclination at the current part of the radiation belt. While the orbit integral flux for protons with energy greater than 10MeV reaches an order of magnitude for some inclination at same location of the radiation belt. The orbit's proton integral flux maximum variation is an order of magnitude. The electron integral flux's variation reaches up to three order of magnitude for some inclination orbit at lowest radiation belt radiation belt. The electron integral flux's maximum vaxiation is one of magnitude lower. The particle environment variation is little at the altitude greater than 1000 km.